
Glass ilJLT 

Book _S.U^14_ 



OKKlCIAr, .UONA'I'H>N. 



MARYLAND GEOLOGICAL SURVEY 



ST. MARY'S COUNTY 



MARYLAND 



GEOLOGICAL SURVEY 




ST. MARY'S COUNTY 



BALTIMORE 

THE JOHNS HOPKINS PRESS 

1907 

Co I'/ 



fl8l 



g„.\A^ 












n.\LTIMORE, MD., U. 8. A. 



D. OF On 
APF 22 908 



COMMISSION 

EDWIK WAEFIELD, President. 

GOVERXOR OF MARYLAND. 

GOKDOK T. ATKINSONS', 

COMPTROLLER OF 5IARYLAXD. 

IRA EEMSEJ^, Executive Officer. 

PRESIDENT OF THE JOHNS HOPKINS UNIVERSITY. 

R. W. SILVESTER, Secretary. 

PRESIDENT OF THE MARYLAND AGRICULTURAL COLLEGE. 



SCIENTIFIC STAFF 



Wm. Bullock Clark, State Geologist. 

superintendent of the survey. 



Edward B. Mathews, 
George B. Shattuck, 

B. L. Miller, 

C. K. Swartz, 
E. W. Berry, 

A. BiBBINS, 



. Assistant State Geologist. 
Geologist. 



Geologist. 
Geologist. 
Geologist. 
Geologist. 



Also with the cooperation of seveial memliers of the scientific bureaus 
of the jSTational Government. 



LETTER OF TRANSMITTAL 

To His Excellency Edwin Warfield, 

Governor of Maryland and President of the Geological Survey 
Commission. 

Si7\- — I have the honor to present herewith a report on The Physical 
Features of St. Mary's County. This volume is the fifth of a series of re- 
ports on the county resources, and is accompanied by large scale topo- 
graphical, geological, and agricultural soil maps. The information con- 
tained in this volume will prove of both economic and educational value 
to the residents of St. Mary's County as well as to those who may desire 
information regarding this section of the State. I am, 

Very respectfully, 

Wm. Bullock Clark, 

State Geologist. 
Johns Hopkins University, 
Baltimore, March, 1907. 



CONTENTS 

PAGE 

PREFACE ^'^ 

INTRODUCTION 21 

DEVELOPMENT OP KNOWLEDGE CONCERNING THE PHYSICAL 
FEATURES OF ST. MARY'S COUNTY, WITH BIBLIOG- 
RAPHY. By George Bukbank Shattuck 25 

Of; 
Introductory 

Historical Review ^^ 

The History of Geographic Research 26 

The History of Geologic Research '^^ 

OQ 

Bibliography "^° 

THE PHYSIOGRAPHY OF ST. MARY'S COUNTY. By George Burbank 



Shattuck 



55 



Introductory 

Topographic Description ^^ 

The Drainage of St. Mary's County 59 

The Structure of the Coastal Plain 61 

Topographic History ^^ 

The Lafayette Stage ^^ 

The Sunderland Stage 62 

63 

\[ 65 

66 



The Wicomico Stage 
The Talbot Stage . . . 
The Recent Stage . . 



THE GEOLOGY OF ST. MARY'S COUNTY. By George Burbank 

Shattuck " ' 

Introductory 

The Miocene "^ 

The Chesapeake Group "^ 

The Calvert Formation 
Areal Distribution 



68 

69 

Strike, Dip, and Thickness "0 

Character of Materials ''1 

Stratigraphic Relations '''^ 

Sub-Divisions '^^ 



12 CONTENTS 

PAGE 

The Choptauk Formation 72 

Areal Distribut ion 73 

Strike, Dip, and Thickness 73 

Character of Materials 74 

Stratigraphic Relations 74 

Sub-Divisions 74 

The St. Mary's Formation 76 

Areal Distribution 76 

Strike, Dip, and Thickness 77 

Character of Materials 78 

Stratigraphic Relations 78 

Sub-Divisions 78 

Local Sections 79 

Origin of Materials 80 

The Pliocenk 81 

The Lafayette Formation 81 

Areal Distribution 82 

Structure and Thickness 82 

Character of Materials 83 

Stratigraphic Relations 83 

Origin of Materials 83 

The Pleistocene 84 

The Columbia Group 84 

The Sunderland Formation 85 

Areal Distribution 85 

Structure and Thickness 86 

Character of Materials 86 

Stratigraphic Relations 87 

Local Sections 90 

The Wicomico Formation 91 

Areal Distribution 91 

Structure and Thickness 91 

Character of Materials 92 

Stratigraphic Relations 92 

Local Sections 93 

The Talbot Formation 93 

Areal Distribution 93 

Structure and Thickness 94 

Character of Materials 95 

Stratigraphic Relations 95 

Local Sections 95 

The Recent Deposits 96 

Origin of Materials 97 



MARYLAND GEOLOGICAL SURVEY 13 

PAGE 

The Interpretation of the Geological Record 98 

Sedimentary Record of the Chesapeake Group 98 

Sedimentary Record of the Lafayette Formation 98 

Sedimentary Record of tlie Columbia Group 99 

THE ECONOMIC RESOURCES OF ST. MARY'S COUNTY. By Benjamin 

L. Miller 113 

Introductory 113 

The Natural Deposits 113 

The Clays 113 

Tertiary Clays 114 

Quaternary Clays 115 

The Sands 117 

The Gravels 118 

The Building Stone 118 

The Marls 119 

The Diatomaceous Earth 120 

The Water Resources 121 

Springs 121 

Dug Wells 122 

Artesian Wells 122 

The Eocene Horizon 123 

The Miocene Horizons 123 

THE SOILS OF ST. MARY'S COUNTY. By Jay A. Bonsteel 125 

Introductory 125 

The Soil Types 126 

The Norfolk Loam 126 

The Leonardtown Loam 127 

The Susquehanna Gravel 129 

The Windsor Sand 130 

The Norfolk Sand 131 

The Sassafras Loam 133 

The Sassafras Sandy Loam 134 

The Meadow Land 136 

The Swamp Land 138 

The Agricultural Conditions 139 

The Transportation Facilities 144 

THE CLIMATE OF ST. MARY'S COUNTY. By C. F. von Herrmann 147 

Introductory 147 

Climatic Data Available for St. Mary's County 148 

The Temperature Conditions 151 

Thermal Anomalies 155 

Precipitation 158 



14 CONTENTS 

PAGE 

The Climatology of Chart/)tte Hai.l ICl 

IXTBODUCTOUY IGl 

The Tempebature Conditions 164 

Duration of Warm Waves 169 

Duration of Cold Periods -. 170 

Duration of the Crop Season 172 

Precipitation 173 

Snowfall 175 

Winds and Weather 176 

THE HYDROGRAPHY OP ST. MARY'S COUNTY. By N. C. Gkover. ... 177 

Chaptico Creek 177 

St. Clement River 178 

Mcintosh Run 178 

THE MAGNETIC DECLINATION IN ST. MARY'S COUNTY. By L. A. 

Bauer 179 

Description of Stations 179 

Meridian Line 180 

THE FORESTS OP ST. MARY'S COUNTY. By C. D. Mell 183 

Introductory 183 

Character and Composition 184 

Types of Forest 187 

Valuable Commercial Trees 188 

Transportation 192 

Present Wood Consumption 192 

Sawmills and Their Products 193 

Cordwood 193 

Railway Ties 194 

Pulpwood 195 

Veneers 196 

Telegraph Poles and Piles 196 

Fence Timber and Staves 197 

Destructive Influences 197 

Forest Fires 197 

Grazing 198 

Other Destructive Influences 199 

Future of the Forest under Judicious Management 200 

Summary 203 

INDEX 205 



ILLUSTRATIONS 

'LATE FACING PAGE 

I. Fig. 1. — View showing topography at Leonardtown 32 

Fig. 2. — View looking up the Patuxent River showing Drum Cliff 32 

II. Fig. 1. — A nearer view of Drum Cliff 56 

Fig. 2. — View showing the fossil bed at Drum Cliff 56 

III. Fig. 1. — View showing the St. Mary's formation overlain by Tal- 

bot, near St. Mary's City 72 

Fig. 2. — A nearer view of the fossil bed shown in Fig. 1 72 

IV. Characteristic fossils of the Miocene of St. Mary's County 80 

V. Fig. 1. — View showing Lafayette-Sunderland scarp, Sunderland 

surface in the foreground, Charlotte Hall 84 

Fig. 2. — View showing Lafayette-Sunderland scarp, Sunderland 

surface in the foreground, near Charlotte Hall 84 

VI. Fig. 1. — View showing section of Sunderland formation near St. 

Mary's City 88 

Fig. 2. — View showing amphitheatre at head of young valley in 

Sunderland formation near Morganza 88 

VII. Fig. 1. — View showing Sunderland surface near Great Mills.... 92 
Fig. 2. — View showing Sunderland-Wicomico scarp, "Wicomico sui-- 

face in the foreground, near Leonardtown 92 

VIII. Fig. 1. — View showing subaerial erosion on Sunderland-Wicom- 
ico scarp, near Leonardtown 96 

Fig. 2. — View showing section in Wicomico formation near 

Clements 96 

IX. Fig. 1. — View showing the fossil bed in the Talbot formation at 

Wailes Bluff 100 

Fig. 2. — View showing the fossil bed in the Talbot formation at 

Wailes Bluff 100 

X. Characteristic fossils of the Pleistocene of St. Mary's County 104 

XI. Fig. 1. — View showing swamp land near Uncle 108 

Fig. 2. View showing barrier beach near Millstone 108 

XII. Fig. 1. — View of St. Jerome Creek showing drowned valleys 

near Ridge 112 

Fig. 2.— View of Breton Bay from Abell's Wharf 112 

XIII. Fig. 1. — View showing mixed forest growth on a clay soil 184 

Fig. 2. — View showing the head of a tidal river 184 

XIV. Fig. 1. — View showing Red Gum growth along streams 188 

Fig. 2. — View showing reproduction of Red Gum 188 

XV. Fig. 1. — View showing growth of Loblolly Pine 192 

Fig. 2. — View showing growth of Scrub Pine 192 

XVI. Fig. 1. — View showing reproduction of Loblolly Pine 200 

Fig. 2. — View showing method of transportation of Loblolly logs 

to the mill 200 



16 ILLUSTRATIONS 

FIGURE PAGE 

1. Diagram showing the approximate position of the shore-line of the 

Sunderland Sea 62 

2. Diagram showing the approximate position of the shore-line of the 

Wicomico Sea 64 

3. Diagram showing the approximate position of the shore-line of the 

Talbot Sea 65 

4. Diagram showing ideal arrangement of the various terrace forma- 

tions in the Maryland Coastal Plain 84 

5. Diagram showing pre-Talbot valley 106 

6. Diagram showing advancing Talbot shore-line and ponded stream.. 107 

7. Diagram showing later stage in advance of Talbot shore-line 108 

8. Ideal section showing advance of Talbot shore-line 109 

9. Temperature curves for Charlotte Hall 166 

10. The warm wave of August, 1900 169 

11. Minimum temperatures during the cold waves of February, 1895, and 

1899 171 

12. Precipitation for each month in the year at Charlotte Hall 175 



PREFACE 

This volume is the fifth of a series of reports dealing with the physi- 
cal features of the several counties of Maryland. 

The Introduction contains a brief statement regarding the location 
and boundaries of St. Mary's County together with its chief physical 
characteristics. 

The Physiography of St. Mary's County, by George B. Shattuck, com- 
prises a discussion of the surface characteristics of the county, together 
with a description both of the topographic forms and of the agencies 
which have produced them. A fuller discussion of this subject has been 
presented by Dr. Shattuck in his report on the Pliocene and Pleistocene 
deposits of Maryland, 

The Geology of St. Mary's County, by George B. Shattuck, deals with 
the stratigraphy and structure of the county. An historical sketch is 
given of the work done by others in this field to which is appended a 
complete bibliography. Many stratigraphical details are presented, ac- 
companied by local sections. 

The Economic Resources of St. Mary's County, by Benjamin L. Miller, 
deals with the economic possibilities of the various geological deposits 
of the county. Those which have been hitherto employed are fully dis- 
cussed, and suggestions are made regarding the employment of others 
not 3'et utilized. 

The Soils of St. Mary's County, by Jay A. Bonsteel, contains a discus- 
sion of the leading soil types of the county and their relation to the sev- 
eral geological formations. This investigation was conducted under the 
direct supervision of Professor Milton Whitney, Director of the Bureau 
of Soils of the U. S. Department of iVgriculture. 

The Climate of St. Mary's County, by C. F. von Herrmann, is an impor- 
tant contribution to the study of the climatic features of the county. 
Mr. von Herrmann is Section Director in Baltimore of the U. S. Weather 



18 PREFACE 

Bureau and is also Meteorologist of the Maryland State Weather 
Service. 

The Hydrography of St. Mary's County, by X. C. Grover, gives a brief 
account of tlie water supply of the county which, as in the case of the 
other Coastal Plain counties, affords but little power for commercial pur- 
poses. The author of this chapter is a member of the Hydrographic Di- 
vision of the U. S. Geological Survey. 

The Magnetic Declination in St. Mary's County, by L. A. Bauer, con- 
tains much important information for the local surveyors of the county. 
Dr. Bauer has been in charge of the magnetic investigations since the 
organization of the Survey and has already published two important 
general reports upon this subject. He is the Director of the Depart- 
ment of International Eesearch in Terrestrial Magnetism of the Car- 
negie Institution. 

The Forests of St. Mary's County, by C. D. Mell, is an important con- 
tribution and should prove of value in the further development of the 
forestry interests of the county. Mr. Mell is a member of the U. S. 
Forest Service. 

The State Geological Survey desires to extend its thanks to the several 
national organizations which have liberally aided it in the preparation 
of several of the papers contained in this volume. The Director of the 
U. S. Geological Survey, the Chief of the U. S. Weather Bureau, the 
Chief of the U. S. Forest Service and the Chief of the Bureau of Soils 
of the U. S. Department of Agriculture have granted many facilities for 
the conduct of the several investigations and the value of the report has 
been much enhanced thereby. 



THE 



PHYSICAL FEATURES 



OF 



ST. MARY'S COUNTY 



THE PHYSICAL FEATURES OF 
ST. MARY'S COUNTY 



INTRODUCTION 

St. Mary's County comprises, with Anne Arundel, Prince George's, 
Charles, and Calvert counties, what is commonly known as Southern 
Maryland and is the most southern county of the group. It is located 
between the parallels 38° 2' and 38° 31' north latitude and the meridians 
76° 19' and 76° 53' west longitude and covers an area of 369.1 square 
miles. St. Mary's was the first county established. N'o record of the 
date of its erection exists, since its jurisdiction at first was co-existent 
with that of the Province. The first evidence of its existence as a county 
is the appointment of a sheriff in January, 1637-8, at the same time a 
sheriff was commissioned for the Isle of Kent, which for a time was 
known as a " Hundred " of St. Mary's County. Pour years later, 1643, 
a county court was established on Kent Island and the Jurisdiction of 
St. Mary's was limited to the Western shore. Settlements at the time 
were only along the shores of the Potomac and Patuxent rivers and thus 
in reality the extent of St. Mary's County was about the same as to-day, 
although technically it may have included all of southern, central and 
western Maryland. 

In 1650 Anne Arundel and old Charles counties were erected out of 
this larger territory to accommodate the new settlement on the Severn 
and the growing one on the Patuxent. By 1654 old Charles County was 
changed to Calvert County, which then included the inhabitants on both 
sides of the Patuxent. St. Mary's County was thus restricted to the 
settlements along the Potomac which did not extend beyond Maryland 
Point at the great bend in the river. By the establishment of Charles 
County in 1658 St. Mary's was finally reduced to its present limits on 



22 INTRODUCTION 

the west, Calvert County may have continued to control the southern 
shore of the Patuxent for a short time, but it seems more probable that 
after 1658 St. Mary's possessed the same limits as are prescribed by her 
boundaries to-day. 

For a short time during the supremacy of the Puritans, from 1654 to 
1656, St. Mary's County was known as Potomac County, Calvert and 
Anne Arundel counties being called Patuxent and Providence counties 
respectively. 

St. Mary's County is very nearly surrounded by navigable waters ex- 
cept along its northern and northwestern boundaries adjacent to Charles 
County. It is bounded on the east by Chesapeake Bay, while its northern 
and southern boundaries are mainly formed by the Patuxent and Po- 
tomac rivers. The Wicomico Eiver forms part of its western boundary. 

St. Mary's County is a peninsula across which from northwest to 
southeast runs an elevated plain which gradually declines from an eleva- 
tion of about 180 feet near Charlotte Hall to 100 feet in the vicinity of 
Ridge. From this highland the streams drain to the north a.ud east by 
short courses into the Patuxent River and Chesapeake Bay and to the 
south and west by longer channels into the Potomac River and its 
tributary streams. The County-town is Leonardtown, situated in the 
south-central part of the county near the head of Breton Bay, an estuary 
of the Potomac River. 

The people of St. Mary's County are chiefly agriculturalists, the soils 
of the county being well adapted to the growth of tobacco, corn, wheat, 
and rye, while small fruits, especially peaches, can be successfully raised. 
Truck farming can also be successfully pursued. The lumbering in- 
terests of the county were important in the early days and with the 
introduction of modern methods of forest management might again be 
revived, as there are many tracts in the county where valuable wood- 
lands could be advantageously developed. 

St. Mary's County is prominently identified with the oyster industry, 
valuable oyster grounds being found along the borders of the county both, 
in the Chesapeake Bay as well as in the Patuxent and Potomac rivers. 
Many of the citizens of the county are employed in the oyster business 



MARYLAND GEOLOGICAL SURVEY 23 

which has been the source of large revenue in the past and under modern 
methods will doubtless again revive. 

The mineral resources of the county are not important, although ex- 
tensive areas are underlain by clay and marl, the former affording the 
basis for the manufacture of common brick, while the latter can at times 
be advantageously employed for the improvement of the land. 

The transportation facilities of St. Mary's County are mainly fur- 
nished by the Baltimore, Chesapeake and Atlantic Eailroad which runs 
frequent boats to the various landings on the shores of the Patuxent 
and Potomac rivers. A branch line connecting with the Popes Creek 
Branch of the Philadelphia, Baltimore and Washington Eailroad reaches 
the northern limits of the county at Charlotte Hall and plans are on foot 
for the extension of this road southward through the county to a terminus 
near Point Lookout. With the completion of this line St. Mary's County 
will be in close communication both by rail and water with Baltimore 
and Washington. 

The present volume contains a discussion of the physiography, geology, 
agricultural soils, hydrography, climate, terrestrial magnetism and for- 
estry of the county, which together constitute the physical features. All 
of these are essential to an understanding of the natural resources and 
possess an interest not only from an economic but from an educational 
view-point. W. B. C. 



DEVELOPMENT OF KNOWLEDGE CONCERN- 
ING THE PHYSICAL FEATURES OF 
ST. MARY'S COUNTY, WITH 
BIBLIOGRAPHY 

BY 

GEORGE BURBANK SHATTUCK 



Introductory. 

The miscellaneous observations made by tlie early explorers of St. Mary's 
County pertained to subjects which have now become distinct fields of 
investigation. Notes which relate to discoveries in geography and 
geology have been gathered from various sources by the author who has 
grouped together the most important of them under their respective 
heads. The review of geographic research begins with a summary of 
the exploration made by Capt. John Smith in 1608 and ends with the 
recent work of the State Geological Survey during the summer of 1906. 
The account of the geologic research begins with Wm. Maclure's investi- 
gations in 1809 and ends with the latest publications made in 1906. 

Historical Review. 
St. Mary's County, which occupies a narrow neck of land between 
Chesapeake Bay on the east and the deep estuary of the Patuxent and 
Potomac rivers on the north and south, is favorably situated for explora- 
tion and colonization and was consequently visited and settled by the 
Europeans at a very early date. As is customary in a new country, 
explorations were at first incomplete and the maps made by the early 
geographers far from correct. But as time advanced and the country 
became more thoroughly explored, the rough preliminary maps were 
replaced by more exact and satisfactory ones. The history of exploration 
3 



26 THE PHYSICAL FEATDKES OF ST. MARY's COUNTY 

in St. Mary's County is, therefore, a narrative of the gradual accumula- 
tion of information which at first was vague and general, but now has 
become definite and specific. 

THE HISTORY OF GEOGRAPHIC RESEARCH. 

The first geographic exploration* in the region which is now known 
as St. Mary's County was carried on by Captain John Smith and a few 
companions in the summer of 1608, although the results were not pub- 
lished until 1612-14. The motive which prompted Smith to this under- 
taking was the exploration of Chesapeake Bay and the adjacent country, 
so that the examination of St. Mary's County was only a portion of the 
work accomplished. His description of the country in the vicinity of 
St. Mary's County is as follows : 

" But finding this Easterne shore, shallow broken Isles, and for the 
most part without fresh water, we passed by the straits of Limbo 
[Hooper or Kedge Straits.] for the Westerne shore; so broad is the 
bay here, we could scarce perceiue the great high clifts on the other side : 
by them we Anchored that night and called them Riccards Cliftes [Cal- 
vert Cliffs]. 30 leagues we sayled more Northwards not finding any 
inhabitants, leaving all the Eastern shore, lowe Islandes, but ouergrowne 
with wood, as all the Coast beyond them so farre as wee could see; the 
Westerne shore by which we sayled we found all along well watered, but 
very mountanous and barren, the vallies very fertill, but extreame thicke 
of small wood so well as trees, and much frequented with wolues, Beares, 
Deere, and other wild beasts. We passed many shallow creekes, but the 
first we found Navigable for a ship, we called Bolus [Patapsco]." 

Smith did not spend in all much more than a month in his exploration 
of Chesapeake Bay, but in this short time gathered material which was 
afterward presented in a remarkably well proportioned map, if one con- 
siders the difficulties which he encountered and the extremely rough 
methods of surveying which he employed. This map remained for a 

^ For illustrations of these early maps and the conditions under which 
they were made, see Mathews, Maps and Mapmakers of Maryland, Md. Geol. 
Survey, vol. ii, 1898, pp. 377-488. 



MAEYLAND GEOLOGICAL SUKVEY 27 

long time unsurpassed and served as a basis of exploration and settle- 
ment. In examining the map which Smith compiled from notes taken 
on this famous voyage of discover)^, one is struck with the accuracy with 
which the main features of St. Mary's County are recorded. The curved 
shore line of Chesapeake Bay from Cedar Point to Point Lookout is 
characteristically portrayed and the irregular courses of the Potomac 
and Patuxent rivers, together with their more important estuaries are 
defined with surprising accuracy and the surface of the county is dotted 
over with names of Indian settlements and with trees of various kinds 
which were probably meant to indicate different types of forest growth. 

In 1635 the Lord Baltimore map appeared. This map included most of 
tidewater Maryland, but when compared with the Smith map of the same 
region, is far less accurate in detail and very much more crude in execu- 
tion. St. Mary's County is well defined and in outlines does not differ 
markedly from the same region represented by Smith. A hillock shows 
roughly the position of the Drum Cliffs and the same methods which 
were used by Smith are employed to represent forests. 

In 1651, the Farrer map of the environs of Chesapeake Bay and the 
surrounding country was published. This map, which was drawn by 
Virginia Farrer, was distorted so as to prove that " in ten dayes march 
with 50 foote and 30 horsemen from the head of leames Eiver, ouer 
those hills and through the rich adiacent Vallyes beautified with proffit- 
able river which necessarily must run into yt peacefull Indian Sea " one 
might arrive in New Albion or California. In this map, the region now 
occupied by St. Mary's County was so distorted that the map was prac- 
tically useless. 

Fiften years later, in 1666, George Alsop published a map which em- 
braced the environs of Chesapeake Bay from a point in Virginia a little 
south of the Potomac Eiver northward to what is now in part Delaware 
and Pennsylvania. The map was issued in a small pamphlet and was 
based on personal observation throughout the region represented. Al- 
though many of the details which were placed on the map had been 
obtained by personal exploration, still Alsop was doubtless familiar with 
the early Smith map and was guided not a little by it. The map is on 



28 THE PHYSICAL FEATURES OF ST. MARY'S COUNTY 

a larger scale and shows more detail than represented by Smith, yet it 
adds little to the real knowledge of the region, because of its diagram- 
matic character and extremely distorted proportions. It is just such a 
map as might be produced by a rover or an untrained hunter who luid 
explored the region in a general way. The representation of the Pa- 
tuxent and Potomac rivers is extremely diagrammatic and conventional 
wliilo tlie St. Clary's Eiver, called by Alsop " S. George River," is the 
only tributary to the Potomac which is represented on the map. The 
other reentrants along the border of the Potomac are represented by 
a wavy outline of the shore. Isolated hillocks are used to indicate 
higher land and scattered trees to represent the presence of forest 
growth. The location of St. Mary's City is indicated by a group of 
houses. 

The map which Smith published in 1613 was not excelled by 
other explorers until 1G70, when Augustin Herrman brought out a map 
of the region extending from southern New Jersey to southern Virginia. 
Herrman, it seems, offered to make a map of Lord Baltimore's territory 
provided Lord Baltimore in return would grant him a manor along Bo- 
hemia Eiver; this proposition was accepted in 1660 and Herrman soon 
after began to fulfil his part of the contract. He was engaged in this 
work for about ten years, and the map which he finally produced indi- 
cates that he had considerable talent, not only as a surveyor, but also as 
a draughtsman. This map was published in 1670 and embraced the 
territory from the southern half of New Jersey to Southern Virginia 
and westward to the limit of tide-water. The cartographic work of 
St. Mary's County was the best which had appeared up to that time. 
The name " St. Mary County " here appears on the map, together with 
a number of the more important settlements scattered over the area. 
The coast line bordering the Bay is represented more accurately than in 
preceding maps and an attempt is made to show the configuration of 
St. Jerome Creek, The winding courses of both the Patuxent and 
Potomac rivers are shown in considerable detail and the position of the 
principal tributaries to both streams is well brought out. Names of 
settlements indicate the location of villages. 



MARYLAND GEOLOGICAL SURVEY 29 



The next general map of the Chesapeake shore to appear was published 
by Walter Hoxton in 1735. Hoxton was a captain in the Merchant 
Marine service between London and Virginia. In regard to his own map, 

he says : 

" In this Draught all the Principal Points, and all the Shoals and 
Soundings are Exactly Laid Down, but as I have not had Opportunity to 
Survey all of ye Bays, Elvers and Creeks, I have distinguisht what is my 
own doing by a Shading within the Line, from the outer part of the 
Coast which to make this Map as complete as at present I am able, have 
borrow'd from the Old Map, & are Traced by a Single Line without 
Shading N. B. The Depths of Water are set down in Fathoms as 
farr np\s Spes Utie Island, but above that in Feet." The particular 
point which is of interest in regard to this chart is the mapping of the 
shore line from Point Lookout northward to North East in Cecil County, 
and the indication of various depths of water in the Bay by means of 
figures placed over the spot where they occur, after the manner still em- 
ployed by the United States Coast and Geodetic Survey. 

In 1776, at about the time of the outbreak of the Revolutionary War, 
Anthony Smith published a chart of Chesapeake Bay on a scale of 3^ 
miles to the inch. This chart was intended for a guide to navigators, 
and such information as shoals, channels, islands, and the various depths 
of water were represented. 

After the close of the war, in 1794, Dennis Griffith assembled all 
available information and published a map of the entire State which was 
not excelled until Alexander began the publication of his maps in the 
fourth decade of the last century. In this map, the shape of St. Mary's 
County was quite accurately portrayed and the configuration of the Bay 
shore was an improvement on that of Herrman, but the shore line of the 
Patuxent River was considerably generalized. There was additional in- 
formation regarding the small streams which drain the surface of the 
region and many of the localities which occur on the most recent maps 

were indicated. 

A marked advance in the cartography of this region occurred in 1835, 
when Prof. J. T. Ducatel, then State Geologist of Maryland, published 



30 THE PHYSICAL FEATURES OF ST. MARY's COUNTY 

his geological report of St. Mary's County. This report was accompanied 
by a map of the region prepared by John H. Alexander. This map of 
St. Mary's County was the best that had been produced and was not ex- 
celled until the present Geological Survey published the St. Mary's 
County map. In the Alexander map, the topography was expressed 
by contours and the map executed on the scale of 1 : 200,000. The promi- 
nent points along the Bay shore and the Patuxent Elver were mapped 
and named, and the little streams which drain the interior of St. Mary's 
County were indicated. A new feature in the map was here introduced 
in the mapping of roads, of which the principal ones were shown. 
Prominent points in the topography were indicated. 

During the summer of 1845, the United States Coast and Geodetic 
Survey began a detailed survey of Chesapeake Bay. Work was com- 
menced first about Havre de Grace and the head of the Bay and by 1851 
had reached as far south as Point Lookout. The Potomac and Patuxent 
rivers were last to receive attention and the latter was not mapped until 
1860. 

The maps, which were subsequently published, attained a very high 
grade of workmanship. Besides the position of the shore line, they in- 
dicated by means of numerals, the depths of water in feet and fathoms, 
the character of the bottom and the topography of the coast for about 
two miles back from the shore line. 

With the exception of the State map published by Martenet in 1865, 
which has been revised from time to time, no other map work of im- 
portance was undertaken until 1890, when the United States Geological 
Survey began systematic topographic work in southern Maryland. In 
that year, the coast line and the interior of St. Mary's County were sur- 
veyed and subsequently published in eight sheets. Each one of these 
sheets, however, included portions of territory lying outside of St. Mary's 
County. These sheets are, beginning with the northern. Prince Fi"ed- 
erick, Brandywine, Drum Point, Leonardtown, Wicomico, Point Lookout, 
Piney Point, and Montross. The cartographic work of the LTnited 
States Geological Survey was in advance of any which had been pre- 
viously attempted in St. Mary's County. The quality of the work was 



MARYLAND GEOLOGICAL SURVEY 31 

no better tlian that published by the United States Coast and Geodetic 
Survey, but while the former confined its efforts mostly to the water- 
ways and mapped the adjacent land only a mile or two from the coast, 
the United States Geological Survey mapped the entire land area. The 
map was printed in three colors, blue, brown, and black. The hydrography 
was represented in blue and went into great details, including not only 
the larger water-ways, but also the smaller streams and their minute 
branches. Kelief was represented by contours with a 20-foot interval 
and printed in brown; while the culture, includiUig highways, bridges, 
railroads, houses, and the names of important localities, was printed in 
black. 

The present Maryland Geological Survey, in co-operation with the 
United States Geological Survey, revised this map in the year 1900, and 
it is on this base that the geologic formations of the county have been 
mapped. 

THE HISTORY OF GEOLOGIC RESEARCH.^ . 

From an early date the attention of geologists has been attracted to 
St. Mary's County. The reason for the great interest in this region is 
probably due not only to the extensive deposits of fossil beds which are 
found within its borders, but also to the fine and continuous exposure 
which is found along the Bay shore and the banks of the Patuxent and 
St. Mary's rivers. The observations which were made led to con- 
clusions which, in the early days of geologic research, were vague and 
oftentimes erroneous; but as time advanced and the principles 
underlying geologic history have become better understood, the papers 
which have been contributed on the region have become more satisfactory 
and the work more explicit and meritorious. As in the geographic re- 
search, so in the geologic, the evolution has been from the vague and 
general to the detailed and specific. 

^ Many of the broad generalizations of the early investigators in southern 
Maryland apply to the entire region although specific localities are seldom 
mentioned. In preparing this historical sketch, it has been necessary to 
refer to these papers although few of them mention the name of St. Mary's 
County. 



32 THE PHYSICAL FKATURES OF ST. MARYS COUNTY 

The first paper of importance was published by William Maclure in 
1809. Although this contribution dealt in a broad way with the geology 
of the United States, yet it shed considerable light on St. Mary's County. 
He included the entire Coastal Plain of Maryland in one formation, the 
" Alluvial," and so represented it on a geologic map. He also described 
the unconsolidated Coastal Plain deposits from Long Island southward, 
indicated the boundaries of the Alluvial formation and noted the pres- 
ence of fossils. This paper was reprinted in substance in various maga- 
zines in 1811, 1817, 1818, and 1826. Maclure's views seem to have 
attracted considerable attention at first, for in 1820 Hayden incorpo- 
rated them in his " Geological Essays " and attempted to establish the 
theory that the Alluvial was deposited by a great flood which came down 
from the north and crossed North America from northeast to southwest. 
The following year Thomas Nuttall referred the Coastal Plain deposits 
to the Second Calcareous formation of Europe, pointed out the fact that 
it occupied the country east of the primitive and transition formations 
of the Piedmont Plateau, and fixed Annapolis as about its northern limit. 

The next year, 1822, Parker Cleaveland brought out his treatise on 
Mineralogy. In this interesting volume he reproduced Maclure's map 
and recorded the occurrence of selenite crystals in the Alluvial soil on 
the St. Mary's bank of tlie Patuxent Eiver. He probably had in mind 
the locality directly opposite Solomons Island. 

Professor John Finch, an Englishman, who was travelling in America 
at about this time, visited the Coastal Plain of Maryland and was so 
impressed with its interesting geology and vast deposits of fossils, that, 
on his return to Europe, he published an account of his experiences in 
southern Maryland, and drew some interesting conclusions regarding its 
geology. Previously, in an article which appeared in 182-1, he took ex- 
ception to the classifications proposed by his predecessors. He believed 
that the deposits included under the term " Alluvial " were contempora- 
neous with the Lower Secondary and Tertiary of Europe, Iceland, Egypt, 
and Hindoostan. He went farther and divided Maclure's " Alluvial " 
up into Ferruginous Sand and Plastic Clay. He believed that the Plastic 
Clay was Tertiary, and based his conclusions on the presence of amber. 



MARYLAND GEOLOGICAL SURVEY. 



ST. MARY'S COUNTY, PLATE I. 




Yic. I. — VIEW SHOWING TOPOGRAPHY .^T LEONARDTOWN. 




Fig. 2.— VIEW looking up the patuxent river showing drum cliff. 



MARYLAND GEOLOGICAL SURVEY 33 

which he found at Cape Sable, correlating it with the amber 
of the Baltic. He also assigned to the Plastic Clay certain of the 
Indian kitchen-middens, which are found along the shore of Chesapeake 
Bay, thus opening a controversy regarding the age of these interesting 
deposits of oyster shells which did not reach a final settlement until 
many years later. He believed that the materials composing his Ferru- 
ginous Sand and Plastic Clay were deposited by a flood from the north 
or the northwest, agreeing somewhat closely with Hayden in this particu- 
lar. His correlations were based almost entirely on lithologic distinc- 
tions, supported by a general similarity of fossil forms. No critical 
study of the fossils was undertaken, however, and few localities were 
given and no geologic boundaries whatever. It is consequently impos- 
sible to ascertain where he intended to place the formations which we 
now ascribe to the Eocene, Miocene, and Pleistocene periods. One thing, 
however, he perceived very keenly — that the deposits in southern Mary- 
land would with future work be separated into many distinct formations. 
This prophecy has since been fulfilled. During the same year Thomas 
Say described the collection of fossil shells made by Finch, and among 
them appeared many forms ivom St. Mary's County. This collection is 
still preserved in the British Museum. 

In the year 1825 J, Van Eenssellaer assigned the deposits of the Coastal 
Plain to the Tertiary, and divided them into Plastic Clay, London Clay, 
and Upper Marine. He further correlated the deposits of Maryland 
which we now know as Miocene with the Upper Marine of Europe and 
probably in part with the London Clay. It should be noted here, how- 
ever, that Finch had previously used Upper Marine in a different sense. 
He had applied it to the sand dune formations of Cape Henry and 
Staten Island, while Van Eenssellaer adopted it for a true fossiliferous 
formation of very much greater age than the deposits which Finch had 
embraced under the same name. Three years later, in 1828, Morton, 
although accepting Van Eenssellaer's correlation of the great deposits of 
fossil shells in the Maryland Coastal Plain with the Upper Marine of 
Europe, apparently used the term in a much wider sense than its author 
had employed. He also gave a list of the fossil forms occurring in the 



34 THE PHYSICAL FEATURES OF ST. MARY'S COUNTY 

Upper Marine, and included some which have since been shown to be 
later than Miocene. During the same year Vanuxem divided the Allu- 
vial and Tertiary of the Atlantic Coast into Secondary, Tertiary, and 
Ancient and j\Iodern Alluvial. In this classification the Miocene of 
southern ]\Iaryland was included in a part of the Tertiary. He stated 
further that vast numbers of " Littoral " shells occurred in the Tertiary 
analogous to those of the Tertiary of the Paris and English basins. 

Conrad brought out his first publications bearing on the Miocene 
geology of Maryland in 1830. He agreed with Vanuxem in placing 
southern Maryland in the Tertiary and pointed out a number of locali- 
ties where fossil shells were found. Two years later Conrad published 
another paper in which he divided up the Coastal Plain deposits into six 
formations. This was the first time that the Coastal Plain had been 
classified so as to show its extreme complexity, and from this time on 
it has been dealt with, not as a deposit containing a few formations but 
as a series of deposits complex in composition and age. Conrad at this 
time ascribed the Miocene of Maryland to the Upper Marine and made 
it equivalent to the Upper Tertiary of Europe. 

The following year John Finch published another book on his travels 
in Maryland which had been made almost a decade before. In this nar- 
rative, Finch gives a most interesting account of the great delight which 
he experienced in collecting from the enormous deposits of fossil shells in 
St. Mary's County. 

The following year Morton published another paper in which he pro- 
posed a classification of the Coastal Plain deposits. In this no distinct 
reference was made to Maryland, but it is probable that he still regarded 
the Miocene of this State as Upper Marine. 

During the same year also Isaac Lea described some fossils from the 
St. Mary's Eiver and regarded then as older Pliocene. He, too, doubted 
the existence of the Miocene in Maryland. 

The next paper of importance was published by Conrad, in 1835, in 
which he assigned the Miocene deposits to the older Medial Pliocene. 
In the following year Ducatel referred the deposits of St. Mary's County 
to older Pliocene and distinctly stated that they were not Miocene. He 



MARYLAND GEOLOGICAL SURVEY 35 

also published a map of southern Maryland in which various deposits 
were marked and the names of the formations given in red letters. 

W. B. Eogers was the first to recognize the presence of Miocene de- 
posits in southern Maryland. He made the announcement in 1836 that 
part of the Maryland Tertiary belonging to the Miocene. He 
noted the great difference between the fossil and living species, 
showing that the Medial Tertiary contained but 19 per cent 
of living forms. He thought that the extermination was 
due to a fall of temperature. In the same and following year he de- 
scribed many fossils from the Miocene of southern Maryland, and in 
1842 he correlated his Medial Tertiary with the Crag of England and 
stated it was Miocene. The boundaries which he gave the Miocene at 
that time were not greatly different from the boundaries which are 
ascribed to the Chesapeake Group of to-day. In 1844, Eogers assigned 
the diatomaceous earth to a position near the base of the Miocene. 

About this time much interest was created in the Miocene problem of 
Maryland by Sir Charles Lyell. He regarded these deposits as Miocene, 
and gave at some length his reasons for this opinion. He also stated that 
the Miocene of Maryland agreed more closely with the Miocene of Lor- 
raine and Bordeaux than with the Suffolk Crag. Lonsdale also con- 
cluded from the corals collected in the Miocene which were submitted 
to him for examination, that the American deposits were probably 
accumulated while the climate was somewhat " superior " to that of the 
Crag and " perhaps " equal to that of the faluns of Lorraine, but " in- 
ferior " to that of Bordeaux. In the same year Conrad described and 
figured many fossils from the Calvert Cliffs. 

No more papers of importance appeared on the Maryland Miocene 
until 1863, when Dana brought out his first edition of the Manual of 
Geology. In this work he took occasion to propose the term " Yorktown 
epoch " for the period during which the Miocene of the Atlantic coast 
was deposited. The next paper of significance was published by Heilprin 
in 1881, in which he discussed the Miocene at some length, and divided 
it into an " Older period " and a " Newer period." The Older period 
contained the older portion of the Miocene of Maryland ; and the Newer 



36 Tin: imiysical fkatluks of st. mary's county 

period, the later portion, lie subdivided the Newer period again into 
the Patuxent Group and the St. Mary's Group. The next year, the same 
autlior revised his classification and divided the ]\Iiocene into three 
groups as follows: the Carolinian or the Upper Atlantic Miocene, in- 
cluding the Sumpter epoch of Dana; the Virginian or Middle Atlantic 
iliocene, including part of the Yorktown of Dana and the Newer group 
of Maryland; and the Maryland ian or the Older Atlantic Miocene, in- 
cluding the rest of Dana's Yorktown and the older period of Mary hind. 
He suggested that the Virginian was of the same age as the second 
Mediterranean of Austrian geologists and the faluns of Touraine, and 
that the Marylandian was, at least in part, equivalent to the first Medi- 
terranean of Austrian geologists and faluns of Leognan and Saucats. 
Three years later the same author published a map sliowing the distribu- 
tion of these formations along the Atlantic coast. In 1888 Otto Meyer 
took exception to Heilprin's correlation and conclusions, and introduced 
the term Atlantic Group to embrace the Tertiary of the Atlantic States, 
and Gulf Group for that of the Gulf States. 

Three years later Darton employed the term " Chesapeake Group " to 
cover a portion of the Miocene, and in the following year Dall and 
Harris published their report on the Miocene deposits in the Correlation 
Papers of the TJ. S. Geological Survey, and used tlie term " Chesapeake 
Group " to include the Miocene strata extending from Delaware to 
Florida. These deposits were made during the Yorktown epoch of 
Dana and the group included a large part of Heilprin's Marylandian, 
Virginian, and Carolinian. Two years later Harris, basing his work on 
a study of the organic remains found in the Miocene, subdivided the 
Miocene faunas of Maryland into the Plum Point fauna, the Jones 
Wharf fauna, and the St. Mary's fauna. 

The following year Darton, by bringing together a large number of 
well records throughout the Coastal Plain from New Jersey southward, 
rendered a most important service to the study of the Miocene problem 
in Maryland by suggesting the structure and extent of the beds through- 
out the region. The following year Dana admitted Harris's faunal 
zones, but still retained the term " Yorktown," to part of which he as- 



MARYLAND GEOLOGICAL SURVEY 37 

signed the Maryland beds. In 1896 Darton published a bulletin under 
the auspices of the U. S. Geological Survey, in which he brought together 
a laro-e number of well records throughout the Coastal Plain. He also 
published the jSTomini folio, and thus was the first to express, on a con- 
tour map, the development of the Miocene throughout a large portion 
of Southern Maryland. 

In 1898 Dall published a most important summary of existing knowl- 
edge of the Tertiary of North America, in which he suggested a classi- 
fication of the Maryland Miocene deposits and correlated them with 
other parts of North America and of Europe. 

Throughout all southern Maryland there is a well-defined mantle of 
clay, loam, sand, and gravel which occupies the divides as well as certain 
of the larger valleys. At first this was confused with the older deposits 
on which it lies and was included with them in all geological discussions 
of the region. Little by little it became apparent that these surficial 
deposits were distinct in age from the more fossiliferous beds beneath, 
but the relation which existed between them was not understood and 
little attention was given to the matter. To go into a full discussion of 
the history of this separation would be to repeat much that has already 
been said. Those who desire to look into the early history in more detail 
are referred to the Keport on the Pliocene and Pleistocene of Maryland, 
Maryland Geological Survey, 1906. It was not until Professor W J 
McGee published his investigations of these deposits in 1887 and 1888 
that their true relation with the underlying formations was at all under- 
stood. He gave the name of Columbia formation to this entire series 
of deposits and divided them into fluviatile and interfluviatile phases 
which he considered contemporaneous. Later, Darton, who took up the 
work where McGee left it, discovered the Lafayette formation in St. 
Mary's County and divided the Columbia formation of McGee into 
an Earlier and a Later Columbia. In 1901, Shattuck, who had studied 
the region in still more detail, separated the same deposits into four 
formations, the Lafayette, Sunderland, Wicomico, and Talbot, the three 
latter of which he united under the general term Columbia Group. He 
also showed that these were developed in terraces lying one above the 



38 THE PHYSICAL FEATURES OF ST. .MARY's COUNTY 

other iu order of their age, tlie oldest lying topographically highest. 
The same year, J. A. Bonsteel published a report on the soils of St. Mary's 
County. 

The next year Shattuck published a report on Cecil County in which 
he referred to the lignite deposits of St. Mary's County and suggested an 
explanation of their origin. In 1904 the Miocene deposits of Maryland 
were fully described by Clark, Shattuck, Dall, Glenn, Martin, and 
others. In this report a geologic map, sections and many photographs 
were published. In 1906 the St. Mary's Folio, by Shattuck and 
Miller, was published by the U. S. Geological Survey. This contained a 
summary of the geology of the county and a geologic map of its south- 
ern portion. Clark and Mathews also published a summar}^ of the physi- 
cal features and geology of Maryland in which St. Mary's County was 
given considerable attention. Before the close of the year the report on 
the Pliocene and Pleistocene deposits of Maryland appeared under the 
authorship of Clark, Shattuck, HoUick, Lucas, and others. In this 
report the surficial deposits of St. Mary's County are discussed at great 
length. 

BIBLIOGRAPHY. 

Containing Eeferences to the Geology and Economic Eesources of 
St. Mary's County. 

1624. 

Smith, John. A Generall Historic of Virginia^ New England, and 
the Summer Isles, etc. London, 1624. [Several editions.] 

(Repub.) The True Travels, Adventures and Observations of Captaine 
lohn Smith in Europe, Asia, Afrika, and America, etc. Richmond, 1819, 2 
vols. — from London edition of 1629. 

Pinkerton's Voyages and Travels, vol. 13, 4to, London, 1812, pp. 1-253 — 
from London edition of 1624. 

Eng. Scholars Library No. 16. (For bibliography of Smith's works and 
their republication, see pp. cxxx-cxxxii.) 

1634. 

Anon. A Eelation of the Successefull beginnings of the Lord Bal- 
temore's Plantation in Mary-Land; Being an extract of certaine I^et- 
ters written from thence, by some of the Adventurers to their friends 
in England. Anno Domini 1634. 

Shea's Early Southern Tracts, No. 1, 23 pp. 4to. 



MARYLAND GEOLOGICAL SURVEY 39 

1807. 

Scott, Joseph. A Geographical description of the states of Mary- 
land and Delaware. Phila., Kimber, Conrad & Co., 1807. 

1809. 
Maclure, Wm. Observations on the Geology of the United States, 
explanatory of a Geological Map. (Eead Jan. 20, 1809.) 
Trans. Amer. Phil. Soc, o. s. vol. vi, 1809, pp. 411-428. 

Maclure, Wm. Observations siir la Geologie des Etats-Unis, sur- 
vant a expliquer une Carte Geologiqne. 

Journ. de phys., de chim. et d'hist. nat., tome Ixix, 1809, pp. 204-213. 

1811. 

Maclure, Wm. Suite des observations snr la Geologie des Etats- 
Unis. 

Journ. de phys., de chim. et d'hist. nat., tome Ixxii, 1811, pp. 137-165. 

1817. 
Maclure, Wm. Observations on the Geology of the United States 
of America, with some remarks on the effect produced on the nature 
and fertility of soils by the decomposition of the different classes of 
rocks. With two plates. 12mo. Phila., 1817. 

1818. 

Maclure, Wm. Observations on the Geology of the United States 
of America, with some remarks on the probable effect that may be pro- 
duced by the decomposition of the different classes of Eocks on the 
nature and fertility of Soils. Two plates. 

Republished in Trans. Amer. Phil. Soc, vol. i, n. s., 1818, pp. 1-91. 

Leon. Zeit, i, 1826, pp. 124-138. 

1820. 
Hayden, H. H. Geological Essays; or an Inquiry into some of the 
Geological Phenomena to be found in various parts of America and 
elsewhere. 8vo, pp. 412. Baltimore, 1820. 

1822. 
Cleavelaxd, Parker. An elementary treatise on Mineralogy and 
Geology. 6 plates. 2d Edit, in 2 vols. Boston, 1822. 



40 THE PHYSICAL FEATURKS OF ST. MARY'S COUNTY 

1824. 

Finch, John. Geological Essay on the Tertiary Formations in 
America. (Eead Acad. Nat. Sci,, Phila., July 15, 1823.) 

Amer. Jour. Scl., vol. vii, 1824, pp. 31-43. 

Say', Tiiojias. An Account of some of the Fossil Shells of !Mary- 
land. 

Jour. Acad. Nat. Sci., Phila., vol. iv, 1824, pp. 124-155. Plates 7-13. 

1825. 

EOBINSON, Samuel, A Catalogue of American Minerals, with their 
localities. Boston, 1825. 

Van Eensselaer, J. Lectures on Geology; being outlines of the 
science, delivered in the New York Antheneum in the year 1835. 8vo. 
pp. 358. New York, 1825. 

1828. 

A^VNUXEM, L., and Morton, S. G. Geological Observations on Sec- 
ondary, Tertiary, and Alluvial formations of the x\tlantic coast of the 
United States arranged from the notes of Lardner Vanuxem. (Eead 
Jan. 1828.) 

Jour. Acad. Nat. Sci., Phila., vol. vi, 1829, pp. 59-71. 

1830. 

Conrad, T. A. On the Geology and Organic Eemains of a part of the 
Peninsula of Maryland. 

Jour. Acad. Nat. Sci., Phila., vol. vi, pt. 2, 1830, pp. 205-230, with two plates. 

1832. 

Conrad, T. A. Fossil Shells of the Tertiary Formations of North 
America illustrated by figures drawn on Stone from Nature. Phila. 
46 pp. [vol. i, pt. 1-2 (1832), 3-4 (1833)]. 

(Repub.) by G. D. Harris, Washington, 1893. 

(Part 3 was republished with plates, March 1, 1835.) 

1833. 
Finch, I. Travels in the United States of America and Canada. 
8vo. 455 pp. London, 1833. 

Lea, Isaac. Contributions to Geology. 237 pp. 6 plates. Phila., 
1833. 

(Rev.) Amer. Jour. Sci., vol. xxv, 1834, pp. 413-423. 



MARYLAND GEOLOGICAL SURVEY 41 

1834. 

DucATEL, J. T., and Alexander, J. H. Keport on the Projected 
Survey of the State of Maryland, pursuant to a resolution of the Gen- 
eral Assembly. 8vo. 39 pp. Annapolis, 1834. Map. 

Md. House of Delegates, Dec. Sess., 1833, 8vo, 39 pp. 

Another edition, Annapolis, 1834, 8vo, 58 pp., and map. 

Another edition, Annapolis, 1834, 8vo, 43 pp., and folded table. 

Amer. Jour. Sci., vol. xxvii, 1835, pp. 1-38. 

1835. 
Conrad, T. A. Observations on a portion of the Atlantic Tertiary 
Region. 

Trans. Geol. Soc, Pa., vol. i, part 2, 1835, pp. 335-341. 

Observations on the Tertiary Strata of the Atlantic coast. 

Amer. Jour. Sci., vol. xxviii, 1835, pp. 104-111, 280-282. 

DuCATEL, J. T. Geologist's report, 1834. 

Another edition. Eeport of the Geologist to the Legislature 

of Maryland, 1834, n. d. 8vo, 50 pp. 2 maps and folded tables. 

DucATEL, J. T., and Alexander, J. H. Eeport on the New Map of 
Maryland, 1834, [Annapolis] n. d. 8vo, '59, i, pp. Two maps and one 
folded table. 

Md. House of Delegates, Dec. Sess., 1834. 

1836. 
Ducatel, J. T. Eeport of the Geologist, n. d. 8vo, pp. 35-84. 
Plate. 

Separate publication (see Ducatel and Alexander). 

Ducatel, J. T., and Alexander, J. H. Eeport on the New Map of 
Maryland, 1835. 8vo, 84, 1 pp. [Annapolis, 1836.] 
Md. Pub. Doc, Dec. Sess., 1835. 
Another edition, 96, 1 pp. and maps and plate. 
Engineer's Report, pp. 1-34; Report of the Geologist, pp. 35-84. 

Eeport of the Engineer and Geologist in relation to the New 

Map to the Executive of Maryland. 

Md. Pub. Doc, Dec Sess., 1835 [Annapolis, 1836], 8vo, 84, 1 pp., 6 maps 
and plates. 

(Rev.) Amer. Jour. Sci., vol. xxx, 1836, pp. 393-394. 

Jour. Franklin Inst., vol. xviii, n. s., 1836, pp. 172-178. 

EoGERS, Wm. B. Eeport of the Geological Eeconnoissance of the State 
of Virginia. Wm. B. Eogers. Phila., 1836. 143 pp. Plate. 



42 THE PHYSICAL FEATURES OF ST. MARY's COUNTY 

1837. 

Ducatel, J. T. Outline of the Physical Geograph}^ of Maryland, 
embracing its prominent Geological Features. 

Trans. Md. Acad. Sci. and Lit., vol. i, 1837, pp. 24-54, with map. 

Ducatel, J. T., and Alexander, J. H. Eeport on the New Map 
of Maryland, 1836. 8vo, 104 pp. and 5 maps. [Annapolis, 1837.] 
Md. House of Delegates, Dec. Sess., 1836. 
Another edition, 117 pp. 

1838. 

Conrad, T. A. Fossils of the Medial Tertiary of the United States. 
No. 1, 1838. [Description on cover 1839 & '40.] 33 pp. Plates 
I-XVII. 

(Repub.) by Wm. H. Dall, Washington, 1893. 

Wagner, William. Description of five new Fossils, of the older 
Pliocene formation of Maryland and North America. (Eead Jan. 1838.) 
Jour. Acad. Nat. Sci., Phila., vol. viii, 1838, pp. 51-53, with one plate. 

1840. 

Conrad, T. A. Fossils of the Medial Tertiary of the United States. 
No. 2. 1840. [Description on cover 1840-1842.] pp. 33-56. Plates 
XVIII-XXIX. 

(Repub.) by W. H. Dall, Washington, 1893. 

1841. 
Conrad, T. A. Description of Twenty-six new Species of Fossil 
Shells discovered in the Medial Tertiary Deposits of Calvert Cliffs, Md. 
Proc. Acad. Nat. Sci., Phila., vol. i, 1841, pp. 28-33. 

1842. 
Conrad, T. A. Observations on a portion of the Atlantic Tertiary 
Eegion, with a description of new species of organic remains. 
2d Bull. Proc. Nat. Inst. Prom. Sci., 1842; plates, pp. 171-192. 

Description of twenty-four new species of Fossil Shells chiefly 

from the Tertiary Deposits of Calvert Cliffs, Md. (Eead June 1, 1841.) 

Jour. Acad. Nat. Sci., Phila., vol. viii, 1842, pp. 183-190. 

Descriptions of new Tertiary Fossils. 

2d Bull. Proc. Nat. Inst. Prom. Sci., 1842, pp. 192-194, two plates. 



MARYLAND GEOLOGICAL SURVEY 43 

Harlan, E. Description of a New Extinct Species of Dolphin from 
Maryland. 

2d Bull. Proc. Nat. Inst. Prom. Sci., 1842, pp. 195-196, 4 plates. 

Markoe, Francis, Jr. [Eemarks and list of fossils from Miocene.] 
2d Bull. Proc. Nat. Inst. Prom. Sci , 1842, p. 132. 

1843. 
Conrad, T. A. Description of a new Genns, and Twentj^-nine new 
Miocene and one Eocene Fossil Shells of the United States. 
Proc. Acad. Nat. Sci., Phila., vol. i, 1843, pp. 305-311. 

1844. 
EoGERS, H. D. Address delivered at the Meeting of the Association 
of American Geologists and jSTaturalists. 

Amer. Jour. Sci., vol. xlvii, 1844, pp. 137-160, 247-278. 

EoGERS, Wm. B. [Tertiar}^ Infusorial formation of Maryland.] 
Amer. Jour. Sci., vol. xlvi, 1844, pp. 141-142. 

1845. 
Conrad, T. A. Fossils of the (Medial Tertiary or) Miocene Forma- 
tion of the United States. No. 3. 1845. pp. 57-80. Plates xxx-xlv. 
(Repub.) by W. H. Ball, Washington, 1893. 

Lyell, Chas. On the Miocene Tertiary Strata of Maryland, Vir- 
ginia and of North and South Carolina. 

Quart. Jour. Geol. Soc, London, vol. i, 1845, pp. 413-427. 
Proc. Geol. Soc, London, vol. i, 1845, pp. 413-427. 

1849. 
Bailey', J. W. New Localities of Infusoria in the Tertiary of Mary- 
land. 

Amer. Jour. Sci., 2d ser., vol. vii, 1849, p. 437. 

GiBBES, E. W. Monograph of the fossil Squalidae of the United 
States. 

Jour. Acad. Nat Sci., Phila., 2 ser., vol. i, 1849, pp. 191-206. 



44 THE PHYSICAL FEATUKHS OF ST. MARY's COUNTY 

1852. 

Desor, E. Post Pliocene of tlie Southern States and its relation to 
the Lanrentian of the North and tlie Deposits of the Valley of the Missis- 
sippi. 

Amer. Jour. Sci., 2d ser., vol. xiv, 1852, pp. 49-59. 

Fisher, E. S. Gazetteer of the State of Maryland compiled from 
the returns of the Seventh Census of the United States. New York 
and Baltimore, 1852, 8vo, 122 pp. 

HiGGiNS, James. The Second Eeport of James Higgins, j\I. D., State 
Agricultural Chemist, to the House of Delegates of Maryland. 8vo. 
118 pp. Annapolis, 1852. 

Md. House of Delegates, Jan. Sess., 1852 [C], 8vo, 126 pp. 

1856. 

HiGGiNs, James. Fifth Agricultural Report of James Higgins, State 
Chemist, to the House of Delegates of the State of Maryland. 8vo. 
91 pp. Annapolis, 1856 (published separately). 

Also Md. House of Delegates, Jan. Sess., 1856. 

Md. Sen. Doc. 

Another edition, pp. 15-18 omitted, 8vo, 90 pp. 

1860. 

Tyson, P. T. First Report of Philip T. Tyson, State Agricultural 
Chemist, to the House of Delegates of Maryland, Jan. 1860. 8vo. 1-15 
pp. Annapolis, 1860. Maps. 

Md. Sen. Doc. [E]. Md. House Doc. [C]. 

1861. 

Conrad, T. A. Fossils of the (Medial Tertiary or) Miocene Forma- 
tion of the United States. No. 4. 1861 (?). pp. 81-89, index and 
plates xlv-xlix. 

(Repub.) by W. H. Dall, Washington, 1893. 

Tyson, P. T. [Letter from Mr. Tyson of Maryland on Tripoli.] 
(Read Dec, 1860.) 

Proc. Acad. Nat. Sci., Phila., vol. xii, 1861, pp. 550-551. 

1862. 
Conrad, T. A. Catalogue of the Miocene Shells of the Atlantic 
Slope. 

Proc. Acad. Nat. Sci., Phila., vol. xiv, 1862, pp. 559-582. 



MARYLAND GEOLOGICAL SURVEY 45 

Tyson, Philip T. Second Eeport of Philip T, Tyson, State Agricul- 
tural Chemist, to the House of Delegates of Maryland, Jan. 1862. 8vo. 
92 pp. Annapolis, 1862. 

Md. Sen. Doc. [F]. 

1864. 

Meek, F. B. Check list of the Invertebrate Fossils of North America. 
Miocene. 

Smith. Misc. Col., vol. vii, art. vii, 1864, 32 pp. 

1866. 
Conrad, T. A. Illustrations of Miocene Fossils, with Descriptions of 
N"e\v Species. 

Amer. Jour. Conch., vol. ii, 1866, pp. 65-74, plates 3 and 4. 

1867. 
Conrad, T. A. Descriptions of New Genera and Species of Miocene 
shells, with notes on other fossil and recent species. 
Amer. Jour. Conch., vol. iii, 1867, pp. 257-270. 

HiGGiNS, James. A Succinct Exposition of the Industrial Eesources 
and Agricultural advantages of the State of Maryland. 

Md. House of Delegates, Jan. Sess., 1867 [DD], 8vo, 109, iii pp. 
Md. Sen. Doc, Jan. Sess., 1867 [U]. 

1871. 

Shaler, N. S. On the Causes which have led to the Production of 
Cape Hatteras. 

Proc. Boston Soc. Nat. Hist., vol. xiv, 1871, pp. 110-121. 

1880. 
Dana, J. D. Manual of Geology. 3d edit. 

1881. 
Heilprin, Angelo. On the Stratigraphical Evidence Afforded by 
the Tertiary Fossils of the Peninsula of Maryland. 
Proc. Acad. Nat. Sci., Phila., vol. xxxii, 1880, pp. 20-33. 



46 THE PHYSICAL FEATURES OF ST. MARY's COUNTY 

1882. 

Heilprin, Angelo. On the relative ages 'and classification of the 
Post-Eocene Tertiary Deposits of the Atlantic Slope. 

Proc. Acad. Nat. Sci., Phila., vol. xxxiv, 18S2, pp. 150-186. 

(Abst.) Amer. Jour. Sci., 3 ser., vol. xxiv, 1882, pp. 228-229. Amer. Nat., 
vol. xvii, 1883, p. 308. 

1881. 
Heilprin, Angelo. The Tertiary Geology of the Eastern and 
Southern United States. 

Jour. Acad. Nat. Sci., Phila., 2 ser., vol. ix, 1884, pp. 115-154, map. 

Contributions to the Tertiary Geology and Paleontology of 

the United States. 4to. 117 pp., map. Phila., 1884. 

Eau, Chas. Prehistoric Fishing in Europe and North America. 
Smithsonian Contrib. Knowledge, vol. xxv, 1884, 360 pp. 

1885. 
Williams, Jr. A. (Editor). Infusorial Earth. 
Mineral Resources U. S., 1883-1884, Washington, 1885, p. 720. 

1888. 

Clark, Wm. B. On three Geological Excursions made during the 
months of October and November, 1887, into the southern counties of 
Maryland. 

Johns Hopkins Univ. Cir. No. 63, vol. vii, 1888, pp. 65-67. 

Uhler, p. E. Observations on the Eocene Tertiary and its Cretaceous 
Associates in the State of Maryland. 
Trans. Md. Acad. Sci., vol. i, 1888, pp. 11-32. 

1890. 
Clark, Wm, B. Third Annual Geological Expedition into Southern 
Maryland and Virginia. 

Johns Hopkins Univ. Cir. No. 81, vol. ix, 1890, pp. 69-71. 

Dall, Wm. H. Contributions to the Tertiary Fauna of Florida. 
Trans. Wagner Free Inst. Sci., Phila., vol. iii, 1890-1895, 570 pp. 

1891. 

Clark, Wm. B. Eeport on the Scientific Expedition into Southern 
Maryland. [Geology; W. B. Clark. Agriculture; Milton Whitney. 
Archaeology; W. H, Holmes.] 

Johns Hopkins Univ. Cir. No. 89, vol. x, 1891, pp. 105-109. 



MARYLAND GEOLOGICAL SURVEY 4 7 

Darton, N. H. Mesozoic and Cenozoic Formations of Eastern Vir- 
ginia and Maryland. 

Bull. Geol. Soc. Amer., vol. ii, 1891, pp. 431-450, map, sections. 
(Abst.) Amer. Geol., vol. vii, 1891, p. 185. 
Amer. Nat., vol. xxv, 1891, p. 658. 

LiNDENKOHL, A. Notos on the submarine channel of the Hudson 
River and other evidences of postglacial subsidence of the middle Atlantic 
coast region. 

Amer. Jour. Sci., 3d ser., vol. xli, 1891, pp. 489-499, 18 plates. 

McGee, W J The Lafayette Formation. 

12th Ann. Rept. U. S. Geol. Surv., 1890-91, Washington, 1891, pp. 347-521. 

WooLMAN, Lewis. Artesian wells and water-bearing horizons of 
Southern New Jersey (with a " note on the extension southward of 
diatomaceous cla3^s and the occurrence there of flowing artesian wells.") 

New Jersey Geol. Surv., Rept. State Geologist for 1890, 1891, pp. 269-276. 

1892. 
Babb, Cyrus C. The Hydrography of the Potomac Basin. 
Amer. Soc. Civ. Eng., vol. xxvii, 1892, pp. 21-33. 

Clark, Wm. B. The Surface Configuration of Maryland. 
Monthly Rept. Md. State Weather Service, vol. ii, 1892, pp. 85-89. 

Dall, W. H., and Harris, G. D. Correlation Papers — Neocene. 

Bull. U. S. Geol. Surv. No. 84, 1892. 

House Misc. Doc, 52d Cong., 1st sess., vol. xliii, No. 337. 

Day, D. T. (Editor). Infusorial Earth. 

Mineral Resources U. S., 1889-90, Washington, 1892, p. 459. 

The statistics for the year are also given in the Eleventh Census. 

ScHARF, J. Thomas. The Natural Eesources and Advantages of 
Maryland, being a complete description of all the counties of the State 
and the City of Baltimore. Annapolis, 1892. 

1893. 
Clark, W. B. Physical Features [of Maryland], pp. 11-54 of Mar}^- 
land, its Eesources, Industries and Institutions. Baltimore, 1893. 

Dall, Wm. H. Eepublication of Conrad's Fossils of the Medial 
Tertiary of the United States. Phila., 1893. 



48 THE PHYSICAL FEATURKS OF ST. MARY's COUNTY 

Darton, N. H. Cenozoic History of Eastern Virginia and Maryland. 

Bull. Geol. Soc. Amer., vol. v, 1893, p. 24. 

(Abst.) Amer. Jour. Sci., 3d sen, vol. xlvi, 1893, p. 305. 

Harris, G. D. The Tertiary Geology of Calvert Cliffs, Maryland. 
Amer. Jour. Sci., 3d ser., vol. xlv, 1893, pp. 21-31, map. 

Republication of Conrad's Fossil Shells of the Tertiary For- 
mations of North America. 8vo. 121 pp. 20 plates. Washington, 
D. C, 1893. 

Whitney, Milton, The Soils of Maryland. 

Md. Agri. Exper. Sta., Bull. No. 21, College Park, 1893, 58 pp., map. 

Williams, G. H. Mines and Minerals [of Maryland]. 
Maryland, its Resources, Industries, and Institutions, Baltimore, 1893, 
pp. 89-153. 

Williams, G. H., and Clark, W. B. Geology [of Maryland], 
Maryland, its Resources, Industries, and Institutions, Baltimore, 1893, pp. 
55-89, 

1894, 
Clark, Wm, Bullock, The Climatology and Physical Features of 
Maryland. 

1st Biennial Rapt. Md. State Weather Service, 1894. 

Darton, N. H. An outline of the Cenozoic History of a Portion of 
the Middle Atlantic Slope, 

Jour. Geol., vol. ii, 1894, pp. 568-587. 

Artesian Well Prospects in Eastern Virginia, Maryland, and 

Delaware. 

Trans. Amer. Inst. Min. Eng., vol. xxiv, 1894, pp. 372-397, plates 1 and 2. 

Fredericksburg Folio. Explanatory sheets. 

U. S. Geol. Surv. Geol. Atlas, folio No. 13, Washington, 1894. 

1896. 
Darton, IST. H. Artesian Well Prospects in the Atlantic Coastal 
Plain Region. 

Bull. U. S. Geol. Surv., No. 138, 1896, 228 pp., 19 plates. 
House Misc. Doc, 54th Cong., 2d sess., vol. — , No. 28. 

■ Nomini Folio, Explanatory sheets. 

U. S. Geol. Surv., Geol. Atlas, folio 23, Washington, 1896. 



MARYLAND GEOLOGICAL SURVEY 49 

1897. 

Bauer, L. A. First Eeport "upon the Magnetic Work in Maryland, 
including the History and Objects of Magnetic Surveys. 
Md. Geol. Surv., vol. i, 1897, pp. 403-529, plates xiv-xvii. 

Clark, Wm. Bullock. Historical Sketch, embracing an Account of 
the Progress of Investigation concerning the Physical Features and 
Natural Eesources of Maryland. 

Md. Geol. Surv., vol. i, 1897, pp. 48-138, plates ii-v. 

Outline of Present Knowledge of the Physical Features of 

Maryland. 

Ibid., vol. 1, 1897, pp. 139-228, plates vi-xiil. 

Maryland Geological Survey, Volume One. 

The Johns Hopkins Press, 1897. ■ 539 pp. Plates and maps. 

Mathews, Edward B. Bibliography and Cartography of Maryland, 
including Publications relating to the Physiography, Geology and Min- 
eral Eesources. 

Md. Geol. Surv., vol. i, 1897, pp. 229-401. 

1898. 
Clark, William Bullock. Administrative Eeport. 
Md. Geol. Surv., vol. ii, 1898, pp. 25-47. 

Dale, W. H. A Table of the Forth American Tertiary Horizons, 
correlated with one another and with those of western Europe, with 
Annotations. 

18th Ann. Rept. U. S. Geol. £urv., 1896-97, Washington, 1898, pp. 323-348. 

Maryland Geological Survey. Volume Two. 
The Johns Hopkins Press, 1898. 509 pp. Plates and maps. 

Mathews, Edward B. An Account of the Character and Distribu- 
tion of Maryland Building Stones, together with a History of the 
Quarrying Industry, 

Md. Geol. Surv., vol. ii, 1898, pp. 125-245. 

The Maps and Map-Makers of Maryland. 

Ibid., pp. 337-488, plates vii-xxxii. 

Merrill, George P. The Physical, Chemical and Economic Proper- 
ties of Building Stones. 

Ibid., vol. ii, 1898, pp. 47-125, plates iv-vi. 



50 THE PHYSICAL FEATURES OF ST. MARY'S COUNTY 

Shattuck, G. B. Two Excursions with Geological Students into the 
Coastal Plain of Maryland. 

Johns Hopkins Univ. Cir. No. 137, vol. xv, 1898, pp. 15-16. 

1899. 
Abbe, Cleveland, Jr. A General Eeport on the Physiography of 
Maryland. 

Md. Weather Service, vol. 1, 1899, pp. 41-21G, plates i-xix. 

Clark, William Bullock. The Eolations of Maryland Topograph}^, 
Climate and Geology to Highway Construction. 
Md. Geol. Surv., vol. iii, 1899, pp. 47-107, plates iii-xi. 

Johnson, Arthur Newhall. The Present Condition of Marjdand 
Highways. 

Ibid., pp. 187-263, plates xv-xxviii. 

Maryland Geological Survey. Volume Three. 

The Johns Hopkins Press, Baltimore, 1899, 461 pp. Plates and maps. 

SioussAT, St. George Leakin. Highway Legislation in Maryland, 
and its Influence on the Economic Development of the State. 
Ibid., pp. 107-187, plates xii-xiv. 

1901. 
Bonsteel, J. A. Soil Survey of St. Mary's County, Md. 
Field Oper. Div, Soils for 1900, U. S. Dept. Agri., Second Rept. Div. Soils, 
1901, pp. 125-145, with map. 

Maryland Geological Survey. Maryland and its Natural Ee- 
scurces. 

Official Publication of the Maryland Commissioners, Pan-American Expo- 
sition, Baltimore, 1901, 38 pp., map. 

Maryland Geological Survey. Maryland and its jSTatural Ee- 

sources. 

Official Publication of the Maryland Commissioners, Inter-state West 
Indian Exposition, Baltimore, 1901, 38 pp., map. 

Shattuck, George Burbank. The Pleistocene Problem of the North 
Atlantic Coastal Plain. 

Johns Hopkins Univ. Circ, vol. xx, 1901, pp. 69-75. 
Amer. Geol., vol. xxviii, 1901, pp. 87-107. 



MARYLAND GEOLOGICAL SURVEY 51 

1902. 

Bauer, L. A. Second Eeport on Magnetic Work in Maryland. 
Md. Geol. Surv., vol. v, Baltimore, 1902, pp. 23-98. With maps. 

Maryland Geological Survey. A^olume Four. 
The Johns Hopkins Press, Baltimore, 1902. 

JSTewton, E. Bullen. List of Thomas Say's types of Maryland 
(U. S.) mollusca in the British Museum. 
Geol. Mag., dec. iv, vol. ix, 1902, pp. 303-305. 

Eies, Heinrich. Eeport on the Clays of Maryland. 
Md. Geol. Surv., vol. iv, 1902, pp. 203-505. 

1903. 

Maryland Geological Survey in co-operation with U. S. Bureau of 
Soils. Map of St. Mary's County showing the agricultural soils. Pub- 
lished on topographic base, prepared for Md. Geol. Surv. by U. S. Geol. 
Surv. 

33% X 38^4, contour 20 feet, 8 colors and patterns, scale 1/62,500. 

in co-operation with U. S. Geological Survey. Map of St. 

Mary's County showing the geological formations. Published on topo- 
graphic base, prepared for Md. Geol. Surv. by U. S. Geol. Surv. 

33% X 38%, contour 20 feet, 7 colors and patterns, scale 1/62,500. 

1904. 

Bagg, Eufus M., Jr. Systematic paleontology of the Miocene de- 
posits of Maryland: Foraminifera. 

Md. Geol. Surv., Miocene, pp. 460-483, plates cxxxi-cxxxiii, 1904. 

Boyer, C. S. Thallophyta-Diatomaceae. 

Md. Geol. Surv., Miocene, pp. 487-507, plates cxxxiv, cxxxv, 1904. 

Case, E. C. Mammalia, Aves, Beptilia. 

Md. Geol. Surv., Miocene, pp. 3-70, plates x-xxvii, 1904. 

Clark, William Bullock. The Miocene deposits of Marjdand. In- 
troduction and general stratigraphic relations. 
Md. Geol. Surv., Miocene, pp. xxiii-xxxii, 1904. 

Echinodermata. 

Md. Geol. Surv., Miocene, pp. 430-433, plates cxix, cxx, 1904. 



52 THE PHYSICAL FEATUllES OF ST. MARY's COUNTY 

Dall, W. H. The Eelations of the Miocene of Maryland to that of 
other regions and to the recent fauna. 

Md. Geol. Surv., Miocene, pp. cxxxix-clv, 1904. 
Abstract: Science, new ser., vol. xix, pp. 502-503, 1904. 

Eastman, C. R. Pisces. 

Md. Geol. Surv., Miocene, pp. 71-93, plates xxviii-xxxii, 1904. 

Glenn, L. C. Pelec3^poda. 

Md. Geol. Surv., Miocene, pp. 274-401, plates Ixv-cviii, 1904. 

HoLLicK, Arthur. Angiospermge. 

Md. Geol. Surv., Miocene, pp. 483-486, Fig. 1, 1904. 

Martin, G. C. Malacostraca, Cirripedia, Mollusca (except Pele- 
cypoda), Brachiopoda, Vermes, Radiolaria. 

Md. Geol. Surv., Miocene, pp. 94-97, 130-274, 402-404, 430, 447-459, plates 
xxxiii-xxxiv, xxxix-lxiv, cix, cxviii, cxxx. 

Shattuck, George Burbank. Geological and Paleontological Ee- 
lations, with a Eeview of Earlier Investigations. 
Md. Geol. Surv., Miocene, pp. xxxiii-cxxxvii, 1904. 

Ulrich, E. 0. Hydrozoa. 

Md. Geol. Surv., Miocene, pp. 433-438, plate cxxi, 1904. 

and Bassler, E. S. Ostracoda, Brj^ozoa. 

Md. Geol. Surv., Miocene, pp. 98-130, 404-429, plates xxxv-xxxvii, cix-cxviii, 
1904. 

Vaughan, T. W. Anthozoa. 

Md. Geol. Surv., Miocene, pp. 438-447, plates cxxii-cxxix, 1904. 

1906. 
Clark, William Bullock and Mathews, Edward B. Eeport on 
the Physical Features of Maryland. 

Md. Geol. Surv., vol. vi, part i, pp. 27-259, plates i-xxiii, 1906. 

Clark, Wm. Bullock, Hollick, Arthur, and Lucas, Frederic 
A. The Interpretation of the Paleontological Criteria. 

Md. Geol. Surv., Pliocene and Pleistocene, pp. 139-152, plates xxxii, xxxiii, 
1906. 

Clark, W. B. Crustacea, Mollusca, Coelenterata, Protozoa. 

Md. Geol. Surv., Pliocene and Pleistocene, pp. 173-210, 213-216, plates xli-lxvi, 
1906. 



MARYLAND GEOLOGICAL SURVEY 53 

Hay, 0. p. Eeptilia. 

Md. Geol. Surv., Pliocene and Pleistocene, pp. 169, 170, pi. xl, 1906. 

HoLLiCK, Arthur. Pteridophyta, Spermatophyta. 

Md. Geol. Surv., Pliocene and Pleistocene, pp. 217-237, plates Ixvii-lxxv, 1906. 

Lucas, F. A. Mammalia. 

Md. Geol. Surv., Pliocene and Pleistocene, 157-169, plates xxxiv-xl, 1906. 

Sellards, E. H. Insecta. 

Md. Geol. Surv., Pliocene and Pleistocene, pp. 170-172, pi. xl, 1906. 

Shattuck, George Burbank. The Pliocene and Pleistocene De- 
posits of Maryland. 

Md. Geol. Surv., Pliocene and Pleistocene, pp. 23-152, plates i-xxxi, 1906. 
Shattuck, Geo. B., and Miller, B. L. 

St. Mary's Folio. 

U. S. Geol. Surv. Geol. Atlas, folio No. 136, Washington, 1906. 

True, Frederick W. Description of a new genus and species of 
fossil seal from the Miocene of Maryland, 

Proc. U. S. Natl. Museum, vol. xxx, pp. 835-840, plates Ixxv-lxxvi, 1906. 

Ulrich, E. 0. Molluscoidea. 

Md. Geol. Surv., Pliocene and Pleistocene, pp. 210-212, fig. 10, 1906. 



THE PHYSIOGRAPHY OF ST. MARY'S COUNTY 

BY 

GEORGE BURBANK SHATTUCK 



Introductory. 

In the main, there are two methods of discussing the physical features 
of a region. The first and older method is to describe in great detail 
the various topographic features which the region possesses, without re- 
gard to their origin, mutual relations, or significance. This method has 
its place and is still used to-day, but is at best a mere catalogue of 
geographic facts. The second and modern method of discussing the 
topography of a region begins where the former leaves off. It assumes 
a knowledge of the leading physical features and seeks to point out the 
relations which they bear to one another as well as the causes which 
have brought them into existence. It will be seen that the latter is the 
more scientific of the two. In discussing the physiography of St. Mary's 
County, both methods will be employed. The topographic history of 
St. Mary's Count}^, although complex and extremely interesting is not as 
diversified as that of many of the other counties of Maryland. The 
reason for this is found in the fact that the county lies entirely within 
the Coastal Plain, while many of the other counties of Maryland lie in 
more than one physiographic province. It is a matter of regret that the 
geologic record of St. Mary's County is so imperfect that many of the 
earlier episodes in its history have been lost entirely or can only be par- 
tially recovered. Other and later portions of its historical record, however, 
are so much more complete that they can be read in their leading features 
as easily as if they had recently occurred. In discussing the physiography 
of St. Mary's County, the topograpliy of the region will be first described 
and then the geologic history which has brought about the principal sur- 
face features will be outlined. 



56 THE PHYSIOGRAPHY OF ST. MARY's COUNTY 

Topographic Description. 
Maryland may be considered as divisible into three grand physio- 
graphic provinces which are, beginning with the eastern, the Coastal 
Plain, the Piedmont Plateau, and the Appalachian Region. The Coastal 
Plain extends from the outer margin of the continental shelf westward to 
the edge of the Piedmont Plateau, or approximately to the position occu- 
pied by the Baltimore & Ohio Railroad as it crosses the State from 
Delaware to Washington. The relief throughout the Coastal Plain re- 
gion is low and its western margin slowly rises to an altitude of about 
300 to 400 feet as it merges with the Piedmont Plateau. The Pied- 
mont Plateau extends from the western margin of the Coastal Plain to 
the eastern boundary of the Appalachian region. It is considerably 
higher than the Coastal Plain, attaining in Carroll County an altitude 
of over 800 feet, and has been deeply dissected by the river valleys which 
cross it. Its western border merges with the Appalachian region at 
Catoctin IMountain. The Appalachian region occupies the remainder of 
the State. It consists of parallel ridges of rugged mountains over 3000 
feet in height, separated by broad valleys and crossed by narrow water 
gaps. Many of the counties of Maryland present a variety of topo- 
graphic features resulting from the fact that they lie in more than one 
of these regions, St. Mary's County, however, lies entirely within the 
Coastal Plain and it is due to this fact that its scenery, although pictur- 
esque and in a measure diversified, does not present the variety which 
is found in some of the other counties of Maryland. In a report on 
Cecil County ^ recently published, two types of the topographic character- 
istics of the Coastal Plain were defined. They were described in the 
following words : " In Cecil County the Coastal Plain contains two con- 
trasted types of topography. One type is a flat, low, featureless plain, 
and the other is a rolling upland attaining four times the elevation of 
the former and resembling the topography of the Piedmont Plateau 
more than that typical of the Coastal Plain. Elk River is the dividing 
line between these two types of topography. On the east side of it is 

' Cecil County, Maryland Geological Survey, 1902 



MARYLAND GEOLOGICAL SURVEY. 



ST. MARY'S COUNTY, PLATE II. 




Fig. I. — A XEARER VIEW OF DRUM CLIFF. 




Fig. 2.^view showing the fossil bed at drum cliff. 



MARYLAND GEOLOGICAL SURVEY 57 

the low land of the typical Coastal Plain and on the west of it are the 
rolling uplands." 

St. Mary's County contains only one type of Coastal Plain topography, 
which is the Western Shore type, but the broad flats along the north 
bank of the Potomac Eiver suggest an Eastern Shore topography. Its 
former level surface has been so extensively dissected by streams which 
run east and northeast into Chesapeake Bay and the Patuxent Eiver on 
the one hand and south into the Potomac Eiver on the other, that the 
country now possesses the character of a rolling upland, such as is custom- 
ary to associate with the eastern margin of the Piedmont Plateau. The 
surface, although resembling a dissected plain, is in reality made up of 
three distinct systems of terraces, which lie above one another like steps 
in a flight of stairs. The oldest, which is topographically highest, occu- 
pies the center and the other terraces are grouped about it in concentric 
arrangement in order of their age. 

The oldest terrace, having been subjected to erosion longer than the 
others, is more dissected and its surface, which was originally level, has 
now been modified so as to present a gently rolling aspect. The next 
younger terrace, although it also has suffered from erosion has not yet 
reached the advanced stage of the oldest, while the terrace which is 
topographically lowest and therefore the youngest of the three has suf- 
fered least of all by erosion and, in fact, has been subjected to the work 
of streams for so short a time that its surface for the most part retains 
its originally level and unbroken character. 

Each of these terraces is separated from the one just below by a well- 
defined scarp-line similar in appearance to the sea-cliff which separates 
the lowest terrace from the modern beach. In approaching the main 
divide of St. Mary's County, one travels for some distance over an 
unbroken flat, which constitutes the lowest and youngest terrace. The 
surface of this plain gradually rises toward the interior. At its inner 
margin, which -is about 45 feet in height, it is terminated by an abrupt 
scarp of 10 to 20 feet, which leads up to the surface of the middle terrace. 
This also is a flat, lying higher than the former and extensively eroded 
by the headwaters of streams which rise within it. This middle flat in 
5 



58 THE PHYSIOGRAPHY OF ST. MARY'S COUNTY 

its turn gently rises toward the interior until at a height of about 75 
or 80 feet it is terminated bv a second scarp some 20 to 30 feet in height, 
which blends at its upper edge with the rolling surface of the highest 
and oldest terrace. The latter is the main divide of the county, although 
not the oldest terrace. It lias suffered greatly from erosion, especially 
along its borders, where it no longer has a plain but a rolling topography. 
This terrace in its turn rises gradually toward the northwest. At a 
height of about 180 feet it is abruptly terminated by a third scarp, which 
rises 20 feet to the surface of the oldest and highest terrace of the 
series. This terrace, which is present in the vicinity of Charlotte Hall, 
is but slightly represented in St. Mary's County. To the northwest in 
Charles and Prince George's counties it has a much more extensive 
development and remnants of it are found scattered along the eastern 
slope of the Piedmont Plateau from Washington northeastward through 
Maryland, Delaware, and Pennsylvania to the Delaware Eiver. It also 
is present in Virginia and southward. In the vicinity of Charlotte Hall 
this terrace is represented by a series of small outliers which bear the 
same relation to the main body of the terrace as the islands scattered 
along the Eastern Shore bear to the mainland behind. 

Throughout the southern half of St. Mary's County, especially in the 
vicinity of Eidge, the inner margins of the three lower terraces do not 
have the same elevations as in tlie region just described. Tlie lowest 
rises from tide to a height of about 10 feet. It is here abruptly ter- 
minated by a scarp about 10 feet high. The next terrace slopes from 
the top of this scarp to a height of about 45 feet. At this point the 
second scarp rises and joins the terrace above at a height of about 60 
feet. Although there is this difference in elevation between the three 
lower terraces in the southern half of the county and the same terraces 
in the northern half, the transition from one to the other is not abrupt 
but gradual and one may trace them as they gently rise from Point 
Lookout northward to the margin of the county. It would appear then 
tliat there has been a slight tilting of the surface in southern St. Mary's 
County. 

To the four terraces just described a fifth may be added, although it 



MARYLAND GEOLOGICAL SURVEY 59 

does not form a conspicuoiis element in the topography. This fifth 
terrace is the beach and wave-bnilt flat which extends along the shore 
of Chesapeake Bay and the Patuxent Eiver. It is everywhere present 
and its width depends in a large measure upon the force of the tidal 
currents which sweep over it. 

When the distribution of terraces on the south bank of the Patuxent 
River is compared with that on the north bank of the Potomac, it will 
be found tliat there is a much greater development of the lowest terrace 
in the valley of the latter. This lack of harmony between the two 
river valleys is apparently due to the erosion of the lowest terrace from 
the south bank of the Patuxent Piiver. From Horse Landing Creek 
southward to Cuckold Creek the lowest terrace has been almost entirely 
removed, but just across the river on the Calvert County side this 
terrace has an extensive development. South of Cuckold Creek the lowest 
terrace is represented by broad flats, but is almost entirely absent from 
the shore of Calvert County on the north bank of the river. It thus 
appears that the Patuxent has removed this terrace first on one and thea 
on the other side of its valley. 

Taken as a whole, the divide of the county is lowest in its southern 
portion between Chesapeake Bay and St. Mary's Eiver, where it has an 
elevation of about 60 feet and rises gradually until its greatest altitude 
is reached near Oaks, where it has a height of about 200 feet. 

THE DRAINAGE OF ST. MARY's COUNTY. 

St. Mary's County, occupying, as it does, the southern extension of 
one of the two peninsulas in Southern Maryland, is entirely surrounded 
by water except along its northwest border, where it joins Charles County. 
Its northeastern margin is washed by the waves of the Patuxent River 
and its eastern and southern margin by those of Chesapeake Bay, the 
Potomac River and its estuaries. These three bodies of water receive 
the drainage of the entire county. The divide which separates the head- 
waters of the streams which flow into the Patuxent-Chesapeake basins 
from those which flow into tlie Potomac River is an extremely irregular 



60 THE PHYSIOGRAPHY OF ST. MARY's COUNTY 

line. It enters St. Man's County near Oaks and runs southward to Point 
Lookout, coincident with the direction of the Three Notch Road. From 
Oaks to Hermanville its general trend is southeast, although it departs 
first on one side and then on the other from this general direction. From 
Hermanville it turns abruptly to the southeast and continues this direc- 
tion to Point Lookout. Throughout its entire course the divide is 
situated northeast or east of the line passing down tlie center of the 
county. 

The most important tributaries of the Patuxent and Chesapeake waters 
are Indian, Trent Hall, Persimmon, Horse Landing, Cat, Cole, St. John, 
and Cuckold creeks, which enter the Patuxent; and St. Jerome and 
Deep creeks, which enter Chesapeake Bay. Most of the streams enter- 
ing the Potomac are much larger and are converted into estuaries through- 
out their lower courses. They are the Chaptico, St. Clement, Mcintosh, 
Herring, St. George, and Smith creeks, and St. Mary^s Eiver. 

As would be expected from the position of the divide, the streams 
which empty into Chesapeake Bay and the Patuxent River are very 
much shorter than those which find their way into the Potomac River. 
They also flow through deep, steep-sided gorges. Those which enter 
the Potomac River have much longer courses and, as a rule, wider valleys 
with more gentle slopes. Tliis difl:'erence between the streams flowing 
north and those flowing south is probably in part due to the more active 
erosion of the Patuxent River and Chesapeake Bay. It will be remem- 
bered also that where these river courses are shorter and steeper, there 
the lowest terrace has sufi'ered most from erosion. Along the Bay shore 
similar conditions held before the second terrace was deposited as are 
now found along the Calvert Cliffs in Calvert County, for at the inner 
margin of this latest terrace there is a steep escarpment which was cut 
in precisely the same manner as Calvert Cliffs are being cut to-day. 
Tlie pusliing back of the shore-line toward the divide so as to throw 
tlie whole out of symmetry was doubtless accomplished while this latest 
terrace was being deposited. 



MARYLAND GEOLOGICAL SURVEY 61 

THE STRUCTURE OF THE COASTAL PLAIN. 

The materials of which this region is built consist of clay, loam, sands, 
gravel, and boulders. These deposits are loose and unconsolidated, ex- 
cept where local ledges of ironstone have been developed. Although the 
materials which have built up St. Mary's County have been deposited at 
various times and belong to a large number of geological horizons, still 
they all lie either horizontal or nearly so. Those which have been tilted 
most, seldom exceed a dip of 12 feet to the mile. The structure of the 
region, therefore, has not materially influenced the drainage, and the 
streams flow from its surface as if they were flowing from a country 
composed of unconsolidated deposits of clays, sands, and gravel hori- 
zontally bedded throughout. 

Topographic History. 
A detailed study of the topographic features which have been described 
above and of the materials out of which the land is composed has re- 
vealed many of the incidents which have produced the present relief. 
An outline of the topographic history will now be given under the follow- 
ing four stages, beginning with the oldest : 

1. The Lafayette Stage. 

2. The Sunderland Stage. 

3. The Wicomico Stage. 

4. The Talbot Stage. 

5. The Eecent Stage. 

THE LAFAYETTE STAGE. 

At the close of the Miocene period the area now occupied by St. 
Mary's County, together with contiguous regions, was raised and sub- 
jected to a long period of erosion. This was followed by a deformation 
of the Middle Atlantic slope of such a character that the Coastal Plain 
was depressed more than the Piedmont region to the west. At this time 
St. Mary's County was entirely submerged and the highest terrace was 
deposited as a thin veneer throughout the region. It is not known how 
far inland the Lafayette sea advanced, but it is probable that its shore- 



62 THE I'liyyiouKAi'jiY of st. mauy's county 

line wrapped about the Piedmont Plateau at an elevation of 500 feet or 
•more above the present sea level, and the valleys of the Appalachian 
region may have been converted into fjords. 



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Fi(i. 1. — Diagram showing the approximate position of the shore-line of the 
Sunderland sea. 

THE SUNDEKLAND STAGE. 

The Lafayette stage of terrace building was brouglit to a close by 
tlie elevation of the region once more above the surface of the ocean. 
]?ain and rivers at once began to erode this new land surface and to 



MARYLAND GEOLOGICAL SURVEY 63 

rapidly remove the materials which the Lafayette sea had but just 
deposited. 

The salient features of the Coastal Plain as a whole, as well as those 
of St. Mary's County, were outlined at this time, although they do 
not appear to have received their full strength and final touches until 
after the close of the Talbot stage. It is probable that the valleys of 
the Potomac and Patuxent rivers, together with their larger tributaries, 
were cut at this time, and that the trough in which Chesapeake Bay 
now lies was also excavated by the Susquehanna River, which flowed 
down from the north and out to the ocean somewhere in the vicinity 
of the present outlet of Chesapeake Bay. It is not probable that at 
this time these depressions were cut to their present depth. They have 
apparently been deepened during each successive uplift. 

At the close of the post-Lafayette elevation the terrace which the 
Lafayette sea had deposited had suffered considerably from erosion, and 
had been so largely removed from St. Mary's County that large areas of 
the underlying miocene deposits were exposed. On this surface the 
Sunderland sea advanced when the region sank once more beneath the 
ocean. The depression during this subsidence was not as great as during 
the Lafayette stage, although when it had reached its maximum the 
county was again submerged with the exception of a few islands near 
Charlotte Hall. The appearance of the region during this maximum 
subsidence is shown in Fig. 1. 

THE WICOilICO STAGE. 

As the region slowly rose above the waves, the terrace which had 
just been deposited by the Sunderland sea was gradually elevated to 
dry land and now forms the main divide of the county. As this surface 
gradually appeared above the ocean, it was vigorously attacked by sub- 
aerial erosion and much of it was destroyed by the rivers, which rapidly 
advanced their valleys across it. After the county had stood for some 
time above the ocean, it was again depressed to receive the waters of 



64 



THE rilYSlOGUAPHY OF ST. ]^[ARy S COUNTY 



the "Wicomico sea. As the ocean advanced once more, the valleys of 
the Patuxent and Potomac river systems were transformed into estuaries, 
Chesapeake Bay took the place of the Susquehanna Eiver, and a narrow 




Fio. 2. — Diagram showing tlie approximate position of tlic shore-line of the 
Wicomico sea. 

neck of land broken into numerous peninsulas, which now corresponds 
to the higher parts of St. Mary's County, was the only portion of the 
region above water. The appearance of the county at this time is 
roughly represented in Fig, 2. 



MARYLAND GEOLOGICAL SURVEY 



65 



THE TALBOT STAGE. 



The Wicomico subsidence^ like those which had preceded it, was brought 
to a close by another elevation of the region, and with the uplift of 
the land the third terrace, which had been deposited by the Wicomico 




Fig. 3. — Diagram showing the approximate position of the shore-line of the 
Talbot sea. 



sea, was raised above the surface of the ocean. Erosion of the entire 
coimty quickly followed the uplift, but had not proceeded far when 
the reo-ion once more sank beneath the water but not to the extent which 



66 THE PlIYSIOUKAPllY OF ST. MARYS COUNTY 

it liad during the previous depression. The appearance of St. Mary's 
County at this time is roughly shown in Fig. o. The lower courses of 
all the river valleys were once more transformed into estuaries and 
along the eastern margin of the county the waves of Chesapeake Bay 
cut a continuous scarp from liermanville to Ridge similar in every 
respect save elevation with the famous Calvert Cliffs which are now 
being cut by the modern waves of Chesapeake Bay. At the base of this 
scarp and around the entire margin of the county the Talbot sea was 
depositing the youngest of the terrace systems which are now elevated 
to form land. 

THE RECENT STAGE. 

Another elevation of the region brought the Talbot stage to a close, 
and the surface was once more attacked vigorously by erosion and finally 
was lowered somewhat beneath the waters of the Patuxent River and 
Chesapeake Bay. There is every reason to believe that this submergence 
is still in progress and that the land is gradually sinking. It is impos- 
sible to say how much the land was elevated at the close of the Talbot 
stage, but it is probable that it stood much higher than it does to-day 
for mud and silt which have been deposited since the close of the Talbot 
stage are now found filling all the estuaries and creeks, not excepting 
the Patuxent River. This filling amounts to about 50 feet. During this 
uplift the Susquehanna River flowed the length of Chesapeake Bay, re- 
ceiving as tributaries all the rivers which now drain the Coastal Plain of 
Maryland and Virginia and reached the ocean some miles beyond the 
present shore line at Cape Henry. At the present time the waves of 
Chesapeake Bay and of the Patuxent River are engaged in cutting against 
the Talbot terrace exactly as the waves during the Talbot stage did 
against the Wicomico terrace, and the waves in the Wicomico stage did 
against the Sunderland terrace. A new terrace is, therefore, being 
formed under the waves below the Talbot and separated from it by a 
well-defined scarp-line. 



THE GEOLOGY OF ST. MARYS COUNTY 

BY 

GEORGE BURBANK SHATTUCK 



Introductory. 

Special attention is given in the following pages to the stratigraphy, 
structure, and areal distribution of the various deposits which are 
found within the borders of St. Mary's County. These deposits 
are all unconsolidated except where the local conditions have pro- 
duced unimportant indurations. The deposits of St. Mary's County are 
among the youngest deposits in Maryland. They do not date back- 
further than the Miocene and extend with occasional breaks down to 
the present. The geologic history of St. Mary's County is complex, how- 
ever, and was frequently interrupted by erosive intervals, so that por- 
tions of the geologic history have been destroyed and lost. These breaks 
are made manifest by the existing unconformities between the beds 
of different materials. 

The various formations of St. Mary's County in their regular sequence 
of superposition arc as follows: 

Age. Formation. Group. 

rTalbot "I 

Pleistocene J Wicomico I Columbia. 

[Sunderland J 

Pliocene Lafayette 

rSt. Mary's I 

Miocene \ Choptank L Chesapeake. 

[Calvert J 

The oldest deposits of St. Mary's County are the three formations of 
the Chesapeake Group, which are Miocene in age. They are, beginning 
with the oldest, Calvert, Choptank, and St. Mary's. In this county, if 
the geological relations are the same as elsewhere, the Calvert formation 
rests unconformably on the Eocene, although the contact is not visible ; 



68 THE GEOLOGY OF ST. MARY'S COUNTY 

the Choptank in turn rests nnconformably on the Calvert, but passes 
into the St. Mary's formation without a break. The materials of the 
formations which compose the Chesapeake Group consist of marls, clays, 
and sands. Each formation is abundantly supplied with fossils. After 
the St. Mary's formation was deposited, the region was elevated and 
extensively eroded, and later submerged to receive the deposits of the 
Lafayette formation. These consist of clay, loam, sand and gravel and 
are deposited in a terrace which is the oldest of the series described above. 
A long period of erosion followed the deposition of the Lafayette terrace 
and the subsidence which brought it to a close permitted the deposition 
of the Columbia formations. These are, beginning with the oldest, 
Sunderland, Wicomico, and Talbot. They are all unconformable with 
whatever lies beneath them, and they are also unconformable with each 
other. They are developed in terraces, lying one above the other, and 
separated by well defined scarp-lines. The materials which enter into 
them are composed of clay, peat, sand, gravel, and ice-borne boulders. As 
a group, they record what took place in St. Mary's County while the 
regions to the north were covered with the great ice sheet. 

The Miocene. 
The Chesapeake Group. 

The Miocene deposits of the Middle Atlantic slope have been de- 
scribed under the name of the Chesapeake Group. In Maryland, the 
materials which compose the formations of this group consist of clay, 
sandy-clay, sand, marl and diatomaceous earth. The sand3^-clay mem- 
bers are, when freshly exposed, greenish to greenish-blue but slowly 
change under the influence of the weather to a slate or drab color. 

It has been found possible to separate tlie beds of the Chesapeake 
Group into three formations, wliicli are designated, beginning with 
the oldest, the Calvert formation, the Choptank formation and the 
St. Mary's formation. 

THE CALVERT FORMATION. 

Calvert County has suggested the name for this formation l)ecause 
of its typical development there. In the famous Calvert Cliffs along 



MARYLAND GEOLOGICAL SURVEY 69 

the eastern border of this county the waves of Chesapeake Bay have 
cut an almost unbroken exposure rising nearly 100 feet in height and 
extending from Chesapeake Beach to Drum Point, a distance of about 
30 miles. 

Areal Distribution. 

The Calvert formation which lies at the base of the Chesapeake Group 
in Maryland crosses the state from northeast to southwest. On the 
Eastern Shore it is found in the southeastern corner of Kent County, 
throughout almost the entire extent of Queen Anne's County and the 
northern portions of Talbot and Caroline counties. 

On the Western Shore the Calvert formation is found extensively 
developed in Anne Arundel, Prince George's, Charles, Calvert, and St. 
Mary's counties. It appears as a long line of outcrop extending from 
the hills near the head of South River estuary to a place on the Calvert 
Cliffs near Point of Eocks. With this breadth, it extends across south- 
ern Maryland from Chesapeake Bay to the Potomac Kiver, and is devel- 
oped along the latter stream from the hills north of Washington to 
the mouth of the Wicomico. 

Notwithstanding this great development, the Calvert formation is 
seldom met with on the surface of the country but must be sought in 
the cliffs of the larger estuaries and in the walls of stream gorges. 
As on the Eastern Shore so on the Western, the Calvert formation is 
covered by younger formations. 

The distribution of the Calvert formation in this county is shown on 
the geological map which accompanies this report. It is found through- 
out the northern portion of the region as far south as a line connecting 
Eoslyn Creek on the Patuxent with the lower portions of St. Clement 
Creek, in the Potomac Valley. Throughout this region the Calvert 
formation is so extensively covered over by the sand and gravels of the 
formations belonging to the Columbia Group that it is nowhere found 
along the divides but occurs in the valley walls of important streams. 
To the north in neighboring regions the Calvert formation lies uncon- 
formably on the eroded surface of the Nanjemoy formation. This rela- 



70 THE GEOLOGY OF ST. MAUY's COUKTY 

tionship is nowhere visible in St. Mary's County, for the Eocene beds 
dip below the surface of the Patuxent Eiver several miles to the north 
of the borders of this county, but there is every reason to believe that 
the same relations hold here as in contiguous regions. The exposures 
of the Calvert formation in this county are neither typical or extensive, 
but uncovered areas are occasionally to be met with in the valleys of 
Indian, Trent Hall, Persimmon, Horse Landing, Cat, and Roslyn creeks 
in the Patuxent Eiver valley, and Chaptico and St. Clement creeks in 
the valley of the Potomac Eiver. 

Strike, Dip and Thickness. 

The strike of the Calvert formation is in general from northeast 
to southwest, but the outcrop frequently becomes very sinuous, because 
of erosion and changes in topography. Thus in the northern portion 
of the county streams have carved out deep valleys, producing a most 
irregular outcrop, which departs widely from the direction of strike. 

The dip is, as a whole, about 11 feet to the mile toward the soutli- 
east. Apart from the exposures in the Calvert Cliffs of this state 
and the JSTomini Cliffs of Virginia, there are no good localities for 
determinin,g the dip, and as it must be calculated as a whole over 
extensive regions, many of them beyond the borders of the county, 
slight changes which may occur are not often brought to light. The 
Calvert formation is not typically developed in St. Maj-y's County and, 
in fact, has almost disappeared beneath the level of tide when it enters 
the northern horders of the region. It is, therefore, not to be found 
lying high in the stream valleys, as in Calvert County, but occupies 
their lower portions and disappears entirely from view in St. Clement 
and Eoslyn creeks. There is, therefore, little opportunity for studying 
the dip of the Calvert formation from its exposures in this county. 

The full thickness of the Calvert formation is likewise not developed 
within the borders of this county and indeed has nowhere been actually 
observed. The formation has been diagonally truncated above by the 
Choptank and younger formations under which it lies unconformably. 
This relation, which is well shown in Calvert, is very nuich obscured 



MARYLAND GEOLOGICAL SURVEY '''1 

in St. Mary's County. The formation appears to thicken rapidly down 
the dip until, at Crisfield, in Somerset County, it shows a thickness 
of 310 feet in an artesian well. As the base of the Calvert formation 
is nowhere visible within St. Mary's County, the thickness of the forma- 
tion must be determined, as was the dip, by studying regions beyond these 
borders. From various calculations it appears that the average thickness 
of the Calv.ert formation in this county is about 185 feet. 

Character of Materials. 
The character of the materials of the Calvert formation are, as a 
whole, quite uniform. They consist of clay, marl, and diatomaceous 
earth. In St. Mary's County only the two former are typically developed. 
The diatomaceous earth is not present as a well defined member. 
Throughout the entire extent the formation is abundantly supplied with 
fossils. These- crumble readily on exposure to the atmosphere and are 
seldom discernible except where active erosion constantly exposes fresh 
surfaces. The clay and marl are dark brown to bluish-green when 
fresh and change to various tints of buff on exposure to the weather. 

Stratigraphic Relations. 
The Calvert formation in St. Mary's County is believed to lie, as 
explained above, unconformably on the eroded edges of the Eocene. 
This unconformity is in the nature of an overlap, but is nowhere visible 
in this region. Above, the Calvert formation lies unconformably be- 
neath the Choptank. 

Sub-Divisions. 
Beyond the borders of this county the Calvert formation falls into two 
divisions which are known as the Fairhaven diatomaceous earth and 
the Plum Point marls. Only one of these sub-divisions, the Plum Point 
marls, is found in this county. These marls consist of a series of sandy 
clays and marls in which are imbedded large numbers of organic remains 
including some diatoms. The color of the material is bluish-green to 



72 THE GEOLOGY OF ST. iMARY S COUNTY 

ffi-eenisli-brown aiul InilT. Fossil remains, althou2;h abundant, throii^h 
the entire member, are usually found massed in beds. In Calvert 
County there arc two of these, from -50 to 35 feet apart, and with a 
thickness varying from 4-\ to 13 feet. In St. Mary's County, however, 
these fossil beds are not conspicuous, but the Plum Point marls, in 
which they are imbedded, may be occasionally seen in the area of the 
Calvert formation, as explained above. On the Potomac Eiver, the 
banks are usually very low and composed of Columbia sand and gravel. 
In consequence of this, the Plum Point marls are seldom met with. 
On the Maryland side of the river they may be seen in the low cliffs 
at the mouth of Choptank Bay, and on the Virginia side a considerable 
thickness of the marls is exposed the entire length of the Nomini Cliffs. 

The actual thickness of the Plum Point marls within St. Mary's County 
is nowhere open to observation and cannot be accurately determined^ 
but it is probable that at least 150 feet of the average thickness of tho 
Calvert formation should be assigned to this sub-division. 

From a detailed study of exposures along the Calvert ClifL's, in Calvert 
County, it has been found possible to sub-divide the Plum Point marls 
into twelve zones. In St. Mary's County it is certain that only the 
higher zones are present, but the lack of exposures has made it impossible 
to determine which or how many of these occur in this county. The 
fact that the Choptank formation lies unconformably above the Calvert 
introduces another element of uncertainty, for some of the higher zones 
found in Calvert County may be absent in this region or the IMum 
Point marls, in St. Mary's County, may contain higher members than 
are to be found in the same division in Calvert County. 

THE CHOPTANK FORMATION. 

The Choptank Eiver has suggested the name for this formation be- 
cause of its great development on the northern bank of that estuary a 
short distance below Dover Bridge in Talbot County. In this locality 
the Choptank formation is very fossiliferous, and may be seen at the 
base of a low cliff which borders the stream for some distance. 



MARYLAND GEOLOGICAL SURVEY. 



ST. MARY'S COUNTY, PLATE III. 




Fig. I. — VIEW showing the st. mary's formation overlain by talbot, near ST. mary's 

CITY. 




Fig. 2. — a nearer view of the fossil fied shown in fig. i. 



MARYLAND GEOLOGICAL SURVEY 73 

Areal Distribution. 
The Choptank formation, which constitutes the second member of 
the Chesapeake Group in Maryland and lies immediately above the 
Calvert formation, is found in Caroline, Talbot, and Dorchester counties, 
on the Eastern Shore, and Anne Arundel, Calvert, Prince George's, 
Charles, and St. Mary's counties on the Western Shore. 

Strike, Dip and Thickness. 

The strike of the Choptank formation is in general from northeast 
to southwest; but because of erosion, particularly on the Western Shore, 
as pointed out above, the outcrop is very sinuous and the strike appears 
to change locally. 

The dip does not appear to be constant throughout the entire extent 
of the formation. In Calvert County, where the Choptank is best 
exposed, the northern portion of the formation down to Parkers Creek 
seems to lie almost horizontal; but south of this point the base of the 
formation dips away at about 10 feet to the mile. Because of this 
structure, the Choptank formation occupies hilltops in the northern por- 
tion of its area and gradually occupies lower and lower levels, until in 
the southern portion of its area it is found in river bottoms and finally 
disappears beneath tide. The best place to examine the dip of the 
Choptank formation is along the Calvert Cliffs between Parker Creek 
and Point of Eocks. Here an almost unbroken exposure may be seen 
dipping gradually toward the southeast. 

The thickness is variable. In the Nomini Cliffs, Virginia, it is 
present as a 50-foot bed between the Calvert formation below and the 
St. Mary's formation above. This is the thickest exposure which is 
open to direct observation. In the well section at Crisfield, mentioned 
above in connection with the Calvert formation, the Choptank forma- 
tion attains a thickness of about 175 feet. It will thus be seen that 
like the Calvert, it thickens as it passes down the dip. The average 
thickness in St. Mar3''s County appears to be about 112 feet. 
6 



74 THE GEOLOGY OF ST. MARY's COUNTY 

Character of Materials. 
The materials composing the Choptank formation are somewhat vari- 
able. They consist of fine, yellow, quartz sand, greenish-blue sandy clay, 
slate-colored clay, and at times ledges of indurated rock. In addition 
to these materials there are abundant fossil remains throughout the 
formation. The sandy phase is well shown in Drum Cliff, on the Pa- 
tuxent, where the indurated layers mentioned above are also visible. 
The clayey phases are not well exposed in this county, but may be seen 
in Calvert County along the Calvert Cliffs, near Point of Eocks, and 
southward. Fossil remains are abundant in Drum Cliff and along the 
branches of Cuckold Creek. 

Stratigrapliic Eelatioiis. 
The Choptank formation lies unconformably on the Calvert forma- 
tion. This unconformity is in the nature of an over-lap but is not 
easily discernible even where the contact is visible. The best place to 
observe it is in that portion of the Calvert Cliff's just below the mouth 
of Parker Creek. Even here, the unconformity cannot be seen while 
standing on the beach but may be observed from a boat a short distance 
from the shore. There are also certain differences between the fauna 
of the Calvert and that of the Choptank. How far this unconformity 
continues down the dip after the beds disappear from view is not known, 
as the data from well records are too meager to draw any conclusion 
regarding this question. Above, the Choptank formation lies conform- 
ably beneath the St. Mary's formation. 

Sub-Divisions. 

The Choptank formation has been subdivided into five zones which 
may be characterized as follows: 

Zone 16. — This zone varies in composition from 5^ellowish sand to 
bluish or greenish sandy clay. It is about 10 feet thick and may be 
found exposed along the Calvert Cliffs from near Parker Creek south- 
ward to a point a little north of Flag Pond, where it disappears be- 
neath the beach. Where the Choptank first makes its appearance in 



MARYLAND GEOLOGICAL SURVEY 75 

the Calvert Cliffs at Parker Creek this zone is absent, and Zone 17. of 
the Choptank rests immediately upon Zone 15 of the Calvert. Zone 16 
is for the most part unfossiliferous, although about 3 miles south of 
Governor Eun a few fossils have been discovered in it, of which the 
following are among the number : EcpJiora quadricostata, Venus cam- 
pechiensis var. cuneata, Dosinia acetabulum, Phacoides contractus, etc. 

Zone 17. — The Choptank formation carries two well-defined fossil 
zones. Of these, Zone 17 is the lower one. The material composing 
this stratum is mostly yellow sand along the Calvert Cliffs. It is 
almost entirely composed of fossils, the yellow sand simply filling in 
the spaces between the organic remains. The fauna of this zone is 
extremely large, but the following will suffice to give an idea of some 
of the tj^pes: 

Ecphora quadricostata, Turritella pleheia, Panopea americana, 
Corhula idonea, C. cuneata, Metis iiplicata, Macrocallista marylandica, 
Venv^ mercenaria, V. campechiensis var. cuneata, Dosinia acetaiidum, 
Isocardia fraterna, Cardium laqueatum, Crassatellites turgidulus, Astarte 
thisphila, Pecten coccymelu^, P. madisoniu^, Melina maxillata. Area 
staminea, etc. 

This zone makes its appearance along the Calvert Cliffs at Parker 
Creek, where it is about 6 feet in thickness, and is continuously exposed 
until it dips beneath tide a little north of Flag Pond. It may also 
be seen at various points on the Patuxent Eiver. It appears to thicken 
considerably southwestward along the strike, for where best exposed 
on the Patuxent Eiver it is at least 18 feet thick near the mouth of 
St. Leonard Creek and over 30 feet thick at Drum Cliff, in St. Mary's 
County. This zone corresponds to " Zone e " of Harris.^ 

Zone 18. — This zone is for the most part unfossiliferous, although 
in places it carries some imperfect fossils and fossil casts. The mate- 
rial of which it is composed is for the most part yellowish sand above 
but grades down into bluish clay below and at times the entire stratum 
is composed of bluish clay. In thickness it varies from 18 to 22 

^ Tertiary Geology of Calvert Cliffs, Maryland. Amer. Jour. Sci., vol. xlv, 
1893, pp. 21-31. 



76 THE GEOLOGY OF ST. ]MARY's COUNTY 

feet along tlie Calvert Cliffs, where it is continuously exposed from 
Parker Creek to a point a few miles south of Flag Pond. Where this 
zone is exposed at Drum ClilT it is thinned down to ahout S feet in 
thickness. 

Zone 19. — This constitutes the upper of the two great fossiliferous 
zones of the Choptank formation. Like Zone 17 it is composed almost 
entirely of fossils with the interstices filled with reddish and yellow 
sand. It varies in thickness from 12 to 15 feet along the Calvert Cliffs 
and is continuously exposed from Parker Creek southward to near Cove 
Point, where the stratum dips heneath the beach. The following is 
a partial list of fossils found in this zone : Balanus concavus, Corhula 
idonea, Macrocallista marylandica, Dosinia acetabulum, Cardium laquea- 
tum, Phacoides anodonta, CrassateUites marylandicus, Astarte thisphila, 
Ostrea carolinensis, Pecten madisonius, Area staminea, etc. This zone 
corresponds to " Zone f " of Harris." 

Zone 20. — This zone lies at the top of the Choptank formation. It 
consists of greenish sand which is frequently oxidized to a red color, 
and at times it carries bands of clay. It seems to be devoid of fossils 
and is 15 feet thick, although it has frequently suffered by erosion. It 
may be best seen near Flag Pond, where it is overlaid by the St. Mary's 
formation. 

THE ST. MARY's FORMATION. 

The name of this formation has been suggested by St. Mary's County 
on account of its great development within that region. The formation 
is found exposed in numerous places along the St. Mary's Piver in the 
vicinity of St. Mary's City. In Calvert County it is best scon along 
the Calvert Cliffs from Point of Pocks southward to Drum Point. 

Areal Distrihution. 
The St. Mary's formation, like the Calvert and the Choptank forma- 
tions, crosses the state from northeast to southwest. On the Eastern 
Shore, it is present, if at all, in Caroline, Talbot, Wicomico and Dor- 
chester counties. 

On the Western Sliore the St. ]\Iary's formation is found developed 

- Loc. cit. 



MARYLAND GEOLOGICAL SURVEY t i 

in southeastern Calvert and St. Mary's counties. In this region 
it is very much obscured by a mantle of younger material be- 
lon^ging to the Columbia Group and is, therefore, seldom seen on the 
surface. Good exposures, however, are found along the Bay shore and 
the Patuxent Eiver and its tributaries. The most extensive exposure 
is found in Calvert County along the Bay shore from Point of Eocks 
to Drum Point. In St. Mary's County the surficial cover of loam and 
gravel has greatly obscured the St. Mary's formation, and consequently 
there are few places where it can be observed. But from the vicinity 
of Hollywood southward to St. Jerome Creek the St. Mary's formation 
is well developed. In the northern portion of its area it occupies the 
higher portions of stream valleys and is underlaid by the Choptank 
formation. Further to the south, in the valley of St. Mary's Eiver, 
the Choptank formation has disappeared and the St. Mary's formation 
is the only representative of the ]\Iiocene. Good exposures of this 
formation may be seen on the Patuxent Eiver, near Millstone, on the 
Bay shore at Langleys Bluff, five miles south of Cedar Point, where it 
forms the base of a section at beach level beneath the overlying fossil- 
iferous beds of the Talbot formation. It also occurs in the valley of 
St. Jerome Creek, and is well developed along the banks of St. Mary's 
Eiver and its tributaries. At Windmill Point on the St. Mary's Eiver, as 
well as on the Patuxent, half a mile west of Millstone, the St. Mary's 
formation contains clusters of gypsum crystals. 

Strike, Dip and Thiclmess. 

The strike of the St. Mary's formation, like that of the two preceding 
ones, is from northeast to southwest. On the Western Shore, because 
of the great diversity in the topography, the outcrop is extremely irregu- 
lar and departs very widely from the direction of the strike. The 
St. Mary's formation rests conformably on the underlying Choptank 
and is overlain unconformably by younger materials. The dip averages 
about 10 feet to the mile toward the southeast. 

The thickness of the St. Mary's formation in southern Maryland 
varies from a few to about 280 feet. In this county, where the formation 
lies between the Choptank beneath and the Sunderland above, it is 



78 THE GEOLOGY OF ST. MARY's COUNTY 

eroded entirely away and disappears in the vicinity of Hollywood. 
Further to the southeast, in the well-boring at Crisiield, it attains a 
thickness of about 280 feet, although it is possible that the upper portion 
of this may be Pliocene. The average thickness of the St. Mary's forma- 
tion in this county is about 140 feet. 

Character of Materials. 
Tlie materials composing the St. Mary's formation are clay, sand, 
and sandy clay. As exposed in this county, it is typically a greenish- 
blue sandy clay bearing large quantities of fossils and resembling very 
closely the sandy clay of the Calvert formation described above. Locally, 
the beds have been indurated by the deposition of iron. 

Stratigraphic Relations. 
The St. Mary's formation lies conformably on the Choptank forma- 
tion. It is overlain unconformably by clays, loams, sands and gravels 
belonging to various members of the Columbia Group. 

Sub-Divisions. 

There are certain faunal differences which separate it from the Chop- 
tank formation. It has been subdivided into the following zones : 

Zone 21. — This zone lies at the base of the St. Mary's formation and 
conformably on the Choptank formation. It consists of a drab clay 
carrying sandy bands of about the same color and appears to be devoid 
of fossils. It may best be seen along the cliffs south of Flag Pond, 
where it has a thickness of about 15 feet. 

Zone 22. — Lying immediately above the last mentioned stratum is 
another band of drab clay in which thin beds of fossils are developed. 
These first made their appearance in the cliffs south of Flag Pond, and 
although the continuity of this bed is interrupted along the Bay shore 
by talus slopes and overgrowth of woodland, still it is believed to be 
continuous with the fossil-bearing beds at the base of the cliff at 
Cove Point. The following are some of the more important fossils 
found in this zone: Balanus concavus, Terehra inornata, Mangilia 
parva, Nassa peralta, ColumheUa communis, Ecphora quadricostata, Tur- 



MARYLAND GEOLOGICAL SURVEY 



^9 



ritella pleheia, T. variabilis, Polynices heros, CorhvJa inequalis, Pecten 
jeffersonius, Area idonea, etc. This stratum is about 14 feet in thick- 
ness. It corresponds to " Zone g " of Harris.^ 

Zone 23.— This zone is composed of drab clay and sand. It has suf- 
fered considerably from erosion, but along the Calvert cliffs it carries 
some fossils of which Turritella plebeia is the most important. It shows 
a thickness of 30 feet, but is unconformably overlain by the Pleistocene 
sands and gravels. 

Zone 24. — A break in the stratigi'aphic continuity of the St. Mary's 
formation occurs south of Drum Point and the exact relation of this 
zone to those preceding is not definitely known. It is believed, how- 
ever, to lie very close to Zone 23. At Chancellor Point on the St. Mary's 
Eiver, where it has been studied, 15 feet of bluish sandy clay are ex- 
posed, overlain unconformably by Pleistocene loams. At this place a 
large number of fossils are present, of which the following may be 
mentioned: Aceteon ovoides, Retusa marylandica, Terehra curvilirata, 
Conus diluvianus, Surcula engonata, Fulgur fusiforme, Turritella varia- 
hilis, Panopea goldfussi, Callocardia sayana, Venus campechiensis var. 
mortoni, Isocardia fraterna, Phacoides anodonta, Pecten madisonius, 
P. jeffersonius, etc. 



Pleistocene. 



Miocene. 



a .2 



^e 



LOCAL SECTIONS. 

I. Section at Drum Cliff near Jones Wharf. 

Feet. Inches. 
Reddish yellow loam, sand, and gravel 42 

fOreenish clay containing poorly preserved remains of 
Balanus concavus, Panopea americana, Phacoides 
contractus, Cardium laqueatum, Pecten madisonius, 

Ostrea carolinensis, etc. (Zone 19, in part) 6 6 

Greenish unfossiliferous clay (Zone 18) 8 

Brownish and greenish fossiliferous sand partially 
indurated above, solidified to solid rock at base, 
carrying the following species : Balanus concavus, 
Ecphora quadricostata var. umhilicata, Turritella 
plebeia, Corhula idonea, Macrocallista marylandica, 
Dosinia acetabulum, Cardium laqueatum, Crassatel- 
lites turgidulus, Astarte thisphila, Pecten madi- 
sonius, Melina maxillata. Area staminea, Scutella 
aherti, etc. (Zone 17, in part) 30 



Total 



6 



^ Loc. cit. 



80 



THK GEOLOGY OF ST. MARY S COUNTY' 



II. Section at Chancellor Point. 



Pleistocene. £ c ^ Sandv loam 

« a 



Feet. 
10 



Miocene. 



'Bluish sandy clay carrying the following fossils : 
Aflaeon oroidcK. Rctiina maryUintliva, Terehra cur- 
vilirata. Conns fliliuiantis, Surcula engonata, Fuhjiir 
fiinifonnc, Tiirritella variabilia, Panoitca goldfussi, 
Callocurdia (Agripoma) sayana, Venus campeclii- 
innis rur. mortoni, Isocardia fraterna, Phacoides 
(Pseiidomiltha) anodonta, Pccten madisoniiis, P. 
jcffetsonius, etc. (Zone 24, in part) 21 



Total 



35 



*J o 
o ~ 

Pleistocene. £ 5 j Section obscured 



III. Section at Cuckold Creek. 



Feet. Inches. 
5 



Miocene. "£, g 

c a 



Dark sandy clay carrying characteristic fossils of Zone 
17. (Zone 17, in part) 

Total 



10 



OIJIGTN OF :\rATERIALS. 

The materials which compose the Miocene deposits of St. Mary's County 
may be divided as regards their origin into two classes, viz., the silicious 
and arenaceous materials, which are land-derived, and the calcareous 
materials, which are of organic origin. The ultimate source of the 
former was doubtless the rocks of the Piedmont Plateau and regions 
beyond in Western Maryland and neighboring territory, but more im- 
mediately they have been derived from older coastal plain deposits; 
the one which enters into the Miocene most conspicuously being the 
Eocene. Near the contact of "the ]\Iiocene and Eocene, a rolled fauna 
derived from the latter is reworked in the former and occasionally 
grains of glauconite, which were in all probability formed in the Eocene 
occur in the lower portions of the Miocene. 

The organic remains, which consist, for the most part, of shells of 
mollusks and bones of vertebrates, are usually in a very good state of 



MARYLAND GEOLOGICAL SURVEY. 



ST. MARY'S COUNTY, PLATE IV. 




CHARACTERISTIC FOSSILS OF THE MIOCENE OF ST. MARY S COUNTY. 



1. Carcharias EGERTONi (Agassiz). 

2. Oliva litterata Lamarck. 

3. ECPHORA QUADRICOSTATA (Say). 

4. FuLGUR FUSiFORME Conrad. 

5. SURCULA BISCATENARIA Conrad. 

6. CoLUMBELLA COMMUNIS (Conrad). 



7. TURRITELLA PLEBEIA Say. 

8. Mangilia parva (Conrad), 
g. Mactra clathrodon Lea. 

10. Arca staminea Say. 

11. Isocardia MARKoiii Conrad. 

12. Spisula subponderosa (d'Orb.). 



13. AsAPHis CENTENARIA (Conrad). 

14. Chione ALVEATA (Conrad). 

15. Pecten madisonius Say. 

16. Venericardia granulata Say. 

17. ScuTELLA aberti Conrad (lateral view). 

18. AsTRANGiA LiNEATA (Conrad). 



MAEYLAND GEOLOGICAL SUKVEY 81 

preservation. They have been but slightly disturbed since deposited 
and evidently now occupy the same relative positions which they did at 
the time when they lived. 

The Pliocene.* 
Within Maryland the Lafayette is the only formation which has been 
referred to this period. The age of the Lafayette has long been in doubt 
and there is not yet sufficient data to correlate it definitely with any 
period. All that can be said is that it is younger than the Miocene which 
it covers and older than the oldest Pleistocene beds found in the same 
vicinity. Within this State no fossils have been found of Pliocene 
age in the deposit. Elsewhere fossil plants and animals alleged to 
hive been discovered within the Lafayette are not of a character suffi- 
ciently definite to determine its age. It is, however, certain that, after 
the deposition of the Miocene beds, there was a long interval of erosion 
before deposition of the Lafayette beds began. Likewise, at the close 
of Lafayette deposition, another long period of erosion occurred before 
the Columbia deposits which are of Pleistocene age were laid down. 
The Lafayette formation thus occupies a stratigraphic position between 
the youngest known Miocene and the oldest known Pleistocene in the 
vicinity, and is separated from each by a long period, during which 
erosion was in progress. These facts, together with the absence of any 
undoubted Pliocene deposits in this region, have led to the reference 
of the Lafayette formation to the latter period. This is, however, only 
a provisional correlation and more positive evidence is needed before 
the question can be regarded as settled. 

THE LAFAYETTE F0R]MATI0N. 

The Lafayette formation has been named from Lafayette County, 
Miss., where Hilgard found it typically developed. It consists of clay, 
loam, sand and gravel mixed together in varying proportions. It is 
developed in a terrace which is stratigraphically older and lies topo- 

* A fuller discussion of the Pliocene in Maryland may be had by consulting 
the report on Pliocene and Pleistocene, Md. Geol. Survey, 1906. 



83 THE GEOLOGY OF ST. MARY's COUNTY 

graphically higher tlian those wliieh constitute tlie various formations 
of the Columbia Group. Since its deposition it has suffered considerably 
from erosion. 

Areal Distribution. 
The Lafayette is one of the most widely developed formations of 
the Coastal Plain, extending from Xew Jersey southward to Florida, 
and thence around the Gulf coast through Texas into Mexico. In 
Maryland it has suffered considerably from erosion since it was deposited, 
and is found best developed between Anacostia Eiver and Charlotte Hall. 
The representatives in St. Mary's County, then, constitutes the southern 
portion of this area. In this county the Lafayette formation occurs as 
isolated outliers which are grouped about Newmarket and Charlotte 
Hall. One of these, the largest, extends from the headwaters of Indian 
Creek to Charlotte Hall, and smaller areas continue the formation south- 
ward along the divide to the vicinity of Mechanicsville. Another area 
lies southwest of JSTewmarket and continues over into Charles County. 
Many streams have forced their headwaters back into the body of the 
Lafayette formation, so that it no longer is as continuous as when first 
deposited, but has developed a sinuous outline. The streams which did 
this cutting and destroyed the continuity of the Lafayette formation in 
St. Mary's County no longer exist. Their valleys are filled in with 
deposits belonging to the Columbia Group. A younger generation of 
streams, however, is rapidly pushing their headwaters backward to 
continue the work of destruction left unfinished by their predecessors. 

Structure and Thickness. 
The base of the Lafayette formation is nowhere visible within St. 
Mary's County, but the surface lies at an elevation of al)0ut 200 feet. 
It is developed as a flat-topped terrace, and it is probable that its average 
thickness is about 30 feet. Within this county no dip or slope are dis- 
cernible, but taking the formation as a whole from Washington City 
southward to Charlotte Hall it has been found to gently decline toward 
the southeast at the rate of 5.5 feet per mile. It is probable tliat this 



MARYLAND GEOLOGICAL SURVEY 83 

attitude has been partly brought about by deformation, while much of 
it must be attributed to the original attitude in which the Lafayette 
was deposited. 

Character of Materials. 
The materials which compose the Lafayette formation in St. Mary's 
County consist of clay, loam and fine gravel. In the railroad cutting 
which passes through the formation at Charlotte Hall there is exposed 
about 20 feet of a brownish-clay loam locally changed to a reddish color 
and bearing fine gravel scattered throughout in ill-defined layers. In 
other places beyond this county, where the Lafayette is typically de- 
veloped, the gravel is much coarser and a bipartite division is discernible 
whereby the finer materials are more abundant toward the top and 
the coarser toward the bottom of the gi-avel, although the gravels are 
frequently found imbedded in the clay and loam above, and these in 
turn are mixed abundantly with the gravel below. There are no good 
sections for studying this deposit in St. Mary's County. 

Stratigraphic Relations. 
The Lafayette formation is built as a terrace, lying unconformably 
and somewhat irregularly on the eroded surface of the Choptank be- 
neath. Its surface constitutes the highest portion of St. Mary's County, 
but its margins are believed to run out under and to be unconformable 
beneath the edges of the Sunderland formation. 

Origin of Materials. 
The materials which compose the Lafayette formation have been 
derived from most of the older rocks in the region throughout which it 
is developed. The clay and loams contain materials re-worked from 
the Miocene, Eocene, Cretaceous, and decomposed crystalline rocks from 
the Piedmont, while the gravels have largely been derived from the quartz 
veins of the Piedmont and the gravel beds of the Potomac. 



8-1 the geology of st. mary s county 

The -Pleistocene. 
The Columbia Group. 
The Columbia Group is the name applied to a series of beds of clay, 
loam, sand, gravel, and ice-borne boulders, which are stratigraphically 
younger and lie topographically below the Lafayette formation. They are 
widely distributed over the surface of the Coastal Plain from Atlantic 
Highlands southward to IMexico and are Pleistocene in age, being the last 
formations which have been laid down in the region before the Eecent 
deposits were formed. The formations which constitute the Columbia 
Group are, beginning with the oldest, the Sunderland, Wicomico, and 
Talbot. These deposits were laid down for the most part during the 



LAFAYETTE 



._ — _-^-' ^A'tr"^-'-'*.'S''i.'^^\ SU NDERLAND 



WICOMICO 



OLDER FORMATIONS 




Fig. 4. — Diagram showing ideal arrangement of the various terrace forma- 
tions in the Maryland Coastal Plain. 

glacial period, but a definite correlation of them with the glacial deposits 
of New Jersey and other regions is not practicable in the present state 
of knowledge. When the field relations which exist between these two 
great classes of deposits are more accurately known, a correlation will, 
no doubt, be possible. The various formations of the Columbia Group 
lie unconformably on whatever rocks are beneath them. The clay, peat, 
loam, sand, gravel, and ice-borne boulders, out of which they are com- 
posed, occur in irregular beds or are developed in lenses. They are 
mixed together in varying amounts and grade over into each other both 
horizontally and vertically. Two of the formations, the Sunderland and 
Talbot, carry determinable vegetable remains, and the latter has yielded 
in addition fragments of fossil insects. The various members of the 
Columbia are developed in terraces lying one above the other in order 
of their age, the oldest occupying topographically the highest position 



MARYLAND GEOLOGICAL SURVEY. 



ST. MARY'S COUNTY, PLATE V. 




Fig. I. — VIEW showing lafayette-sunderland scarp, Sunderland surface in the 

FOREGROUND, CHARLOTTE HALL. 




Fig. 2. — view showing lafayette-sunderi.and scarp, sunderland surface in the 
foreground, near charlotte hall. 



MARYLAND GEOLOGICAL SURVEY 85 

(Fig. 4). They all dip gently toward the surroimding waters and to- 
gether are widely distributed over the surface of the county and obscure 
in a great measure the older deposits which lie beneath them. 

THE SUNDERLAND FORMATION. 

The Sunderland formation has been named from its typical develop- 
ment near the hamlet of Sunderland in Calvert County. It consists of 
a wave-built terrace, which was formed by the waters of the Atlantic 
Ocean or its estuaries when the country stood at a lower level than to-day. 
It is distributed over the entire county occupying the divides between 
the headwaters of the principal streams. Since the time of deposition, 
the Sunderland formation has suffered extensively from erosion. Water- 
ways have opened up their valleys through it and have transformed a 
once continuous mantle of loam and gravel into a series of isolated 
patches with sinuous outlines occupying the higher portions of the 
county, and its once level surface has now been changed by the same 
processes into a gently rolling upland. 

Ai-eal Distrihidion. 

The Sunderland formation is the most widely developed of the 
Pleistocene deposits in St. Mary's County. With the exception of the 
isolated outliers of Lafayette in the vicinity of Charlotte Hall, it occu- 
pies the highest divides from the northern margin of the county, near 
Indian, southward to Eidge, near Point Lookout. On either side in both 
the valleys of the Patuxent and Potomac rivers, as well as in the gorges 
of the streams which are tributary to these estuaries, the Sunderland 
formation is surrounded by terraces of the younger formations of the 
Columbia Group, which lie beneath it. These terraces are more ex- 
tensively developed in the Potomac than in the Patuxent Valley. 

Many streams have forced their headwaters back into the body of the 
Sunderland formation, so that it is no longer as continuous as when 
first deposited, but has developed a sinuous outline. 



86 THE GEOLOGY OF ST. MARY'S COUNTY 

Structure and Thickness. 

In the northern portion of St. Mary's County the base of the Sunder- 
land formation lies at al)ovit 9-5 or 100 feet, while in the southern 
portion near Eidge it is obscured by deposits belonging to the Wicomico 
formation and is not visible. In the vicinity of Charlotte Hall the 
surface of the Sunderland lies at about ISO feet and at Eidge at about 
60 feet. This difference in elevation of 120 feet between the two locali- 
ties, which are 34 miles apart, amounts to a slope toward the southwest 
of 3.5 feet per mile. This gentle decline is probably in large part 
due to the original slope of the surface which was imparted to it while 
it was undergoing deposition beneath the surface of the Sunderland 
sea. There is, however, a slight element of tilting downward toward 
the southeast which is more prominent in the southern portion of the 
county than elsewhere. The surface of the Sunderland at Eidge is the 
lowest which has been observed anywhere in Maryland; it is probably 
due to both tilting and initial slope. The deformation in this region 
exhibited in the Sunderland formation is also found in both the Wicomico 
and Talbot formations, which here also lie lower than elsewhere in 
Maryland. 

The thickness of the Sunderland formation is variable, but averages 
about 35 feet. 

Character of Materials. 

The materials which compose the Sunderland formation consist of 
clay, loam, peat, sand, gravel, and ice-borne boulders. These, as a rule, 
do not lie in well-defined beds, but grade into each other both vertically 
and horizontally. The coarser materials, with the exception of ice-borne 
boulders, are usually found with a cross-bedded structure, while the 
clays and finer materials are either developed in lenses or are horizontally 
stratified. The ice-borne blocks are scattered through the formation 
and may occur in the gravel beneath or in the loam above. There is 
distinguishable throughout the formation a tendency for the coarser 
materials to occupy the lower portions and the finer the upper portions 
of the formation, but the transition from one to the other is not marked 



MARYLAND GEOLOGICAL SURVEY 87 

by an abrupt change. The coarser materials are frequently found above 
in the loam and the finer materials below in the gravel. Many of these 
materials are in an advanced stage of decay. 

StratigrapJiic Relations. 

The SuDflerland formation is built as a terrace, lying unconforniably 
and somewhat irregularly upon the older Miocene and Lafayette de- 
posits. This terrace was laid down about the margin of the Lafayette 
formation and the attenuated edges of the latter are believed to run 
out unconformably for a short distance beneath it. At Charlotte Hall 
the Sunderland formation is separated from the Lafayette by a well- 
defined scarp about 20 feet in height which resembles topographically 
a wave-cut cliff, softened by subaerial erosion. The surface of the Sun- 
derland formation forms the surface of the high divide of St. Mary's 
County, except along its margin, where it seems to pass beneath the 
Wicomico as the margin of the Lafayette does beneath the Sunderland 
at Charlotte Hall. 

A word may be added regarding the scarp at Charlotte Hall, as it 
seems to have been overlooked by former geologists. The height of the 
scarp is about 20 feet and separates the flat surface of the Lafayette 
above from the plain surface of the Sunderland below. The Lafayette 
surface stretches away in an unbroken plain, gently rising toward the 
Piedmont, and the Sunderland extends southward toward the ocean. 
Just beyond the main scarp-line there are in the vicinity of Charlotte 
Hall a number of outliers of Lafayette which rise above the general 
flat of Sunderland. These bear the same relation to the main Lafayette 
deposit as the outliers of the Talbot formation, which now rise above the 
surface of Chesapeake Bay, bear to the mainland close by. This topogra- 
phy at Charlotte Hall might be easily overlooked by one making a 
hurried reconnaissance, and might be entirely misunderstood by one 
unaccustomed to the geology of the Coastal Plain. The narrow, flat re- 
entrants which separate the main body of the Lafayette from the out- 
liers might be looked upon as a valley cut by stream erosion and the 
presence of opposing scarps where the outliers face the main body of 



88 THE GEOLOGY OF ST. MAUY's COUNTY 

the Lafayette formation might be considered as indicative of river banks. 
On the southeast side of these outliers, where they face toward the 
Sunderland sea, there is no opposing bank, but they drop away to the 
Sunderland surface, which is unobstructed by other prominences toward 
the southeast. It is evident that th^e outliers were once portions of 
the mainland and that the narrow flats which ramify among them were 
formerly stream valleys cut in the body of the Lafayette formation, 
but with the advance of the Sunderland sea these drainage ways were 
submerged and filled and the divides which separated them were either 
submerged or else cut up into a sei'ies of outlying islands. A similar 
topography may be seen on the Eastern Shore of Chesapeake Bay 
to-day. 

Another line of evidence is furnished by the presence of a beach 
gravel on the surface of the Sunderland formation as it approaclies the 
base of the Sunderland-Wicomico scarp. The Lafayette in this region 
carries very little gravel and waves cannot produce a shingle beach 
unless there is gravel at hand out of which to make it. At Charlotte 
Hall the waves of the Sunderland sea concentrated on the beach the 
small amount of gravel which they secured by the erosion of the Lafayette 
scarp. It may also be addc'd that there are ice-borne blocks in tlie body 
of the Sunderland formation beneath the scarp-line, but none have yet 
been discovered in the Lafayette formation above. 

An even more significant feature of the topography in the \'ieinity 
of Charlotte Hall is furnished by two generations of stream valleys. 
One of these, the older, is now dry and unoccupied. It penetrates the 
Lafayette formation and formerly drained from it into the Simderland 
sea. The other generation of valleys are now being rapidly extended 
inland from the Patuxent and Potomac rivers. They are steep-walled 
and V-shaped and at the present time have worked their way so far 
back on the divide as to drain the edge of the Sunderland formation 
in the vicinity of Charlotte Hall. These two valley streams not only 
are distinct in age, but they have no physical connection whatsoever. 

In almost every place where good sections of Pleistocene materials are 
.exposed the deposit from base to top seems to be a unit. In other places. 



MARYLAND GEOLOGICAL SURVEY. 



ST. MARY'S COUNTY, PLATE VI. 




Fig. I. — VIEW showing section of Sunderland formation near st. mary s city. 




Fig. 2. — VIEW showing amphitheatre at head of young valley in SUNDERLAND FORMA- 
TION NEAR MORGANZA. 



MARYLAND GEOLOGICAL SURVEY 89 

however, certain layers or beds are sharply separated from underlying 
beds by uneven lines similar to the irregular lines of a cross-bedded de- 
posit. These breaks disappear in short distances, showing clearly that 
they are only local phenomena within the same formation produced by 
the contemporaneous erosion of shifting shallow-water currents, and in 
closely adjoining regions they seem to have no relation to each other 
Since the Pleistocene formations occupy so nearly a horizontal position 
it would be possible to connect these separation lines if they were sub- 
aerial erosional unconformities. In the absence of any definite evidence 
showing these lines to be stratigraphic breaks separating two formations^ 
they have been disregarded. Yet it is not improbable that in some places 
the waves of the advancing -sea in Sunderland, Wicomico, and Talbot 
times did not entirely remove the beds of the preceding period of deposi- 
tion over the area covered by the sea in its next transgression. Especially 
would deposits laid down in depressions be likely to persist as isolated 
remnants which later were covered by the next mantle of Pleistocene ma- 
terials. If this is the case each formation from the Lafayette to the 
Wicomico is probably represented by fragmentary deposits beneath the 
succeeding Pleistocene formations. Thus in certain sections the lower 
portions may represent an earlier period of deposition than that of the 
overlying beds. In those regions where older materials are not exposed 
in the base of the escarpments each Pleistocene formation near its inner 
mavgin probably rests upon the attenuated edges of the next older forma- 
tion. Since lithologic differences furnish insufficient criteria for the 
separation of these late deposits and sections are not numerous enough 
to distinguish between local inter-formational unconformities and wide- 
spread unconformities resulting from an erosion interval, the whole 
mantle of Pleistocene materials occurring at any one point is referred 
to the same formation. The Sunderland is described as overlying the 
Jurassic (?), Cretaceous, Eocene, and Miocene deposits and extending 
from the base of the Lafayette-Sunderland escarpment to the base of the 
Sunderland-Wicomico escarpment. The few deposits of Lafayette ma- 
terials which may possibly underlie the Sunderland are disregarded be- 
cause unrecognizable. Similarly the Wicomico is described as including 
7 



90 



THE GEOLOGY OF ST. :MAnY 8 COIXTY 



all the gravels, sands, and clays overlying the pre-Lafayette deposits 
and extending from the base of the Sunderland-Wicomico escarpment to 
the base of the Wicomico-Talbot escarpment. Perhaps, however, ma- 
terials of later age may occasionally rest upon remnants of the Lafayette 
and Sunderland formations, and the same is true of the Talbot formation. 

Local Sections. 
The matci'ials which compose the Sunderland formation vary rapidly 
from place to place. The following sections, however, will give an idea 
of the character of this formation. 



Pleistocene. 



Miocene. 



I. Section in road leading from Lronardtown in Whnrf. 

1 § f '^*^*^*- 

Z -J J Tougli red sandy clay and gravel 20 

■S E I Sandy clay carrying decomposed gravel and boulders. . . 10 

M si C 

a 2 

_5 "-^ I Greenish sandy clay 20 



o a I Obscured 50 



-■ O 



Total 100 



II. Section 1 mile west of Leonardtoivn on road leading toward Mcintosh Run. 

Feet. Inches. 

Yellow sandy clay 3 

Drab sandy clay and gravel with red mottling 5 

Drab sandy clay with red mottlings carrying boulders. 1 

Drab sandy clay and gravel with red mottlings 3 tJ 

Red sandy clay and gravel 5 

Red sandy clay carrying gravel and decayed chert 

pebbles 4 

Obscured 16 



Pleistocene. 



li^ 



Miocene. 



= 1 

S tj Fine bedded sand and gravel 3 

o S I Reddish sand, depth unknown 10 

^1 L — 

Total 51 



r- O 



III. Section on road at St. Clement Creek 1.5 miles north of Morganza. 

Feet. Inches. 

Brownish red sand 3 6 

Iron crust 2 



Fossil iferous sandy clay 48 

Total 51 



Pleistocene. 


Z 2 




















OJ fei 




•^ 9 




a .2 




rt *- 


Miocene. 


a g 




o' d 




51 



MARYLAND GEOLOGICAL SURVEY 91 

THE WICOMICO FORMATION. 

The next younger formation of the Columbia Group is the Wicomico. 
It has received its name from the Wicomico Eiver in Charles and St. 
Mary's counties, for in the valley of this estuary it is found well de- 
veloped. Like the Sunderland, it consists of clay, loam, sand, gravel, 
and ice-borne boulders which were deposited by the waters of Chesapeake 
Bay and its estuaries. Since its deposition it has suffered considerably 
from erosion. 

Areal Distribution. 

The Wicomico formation is not as extensively developed in St. Mary's 
County as its predecessor, the Sunderland. It is developed as a terrace, 
occupies a lower level and wraps about the margin of the Sunderland 
formation like a border. The formation can be best seen in the valleys 
of the Patuxent and Potomac rivers, and also in gorges of the larger 
estuaries tributary to the latter. x\mong these can be mentioned Wi- 
comico and St. Mary's rivers, and St. Clement and Breton Bays. Ex- 
tensive areas of the Wicomico formation are also found in the higher 
valleys of streams emptying into these estuaries and along the eastern 
margin of St. Mary's County facing Chesapeake Bay. 

Many streams have forced their headwaters back into the body of 
the Wicomico formation, so that it no longer is as continuous as when 
first deposited, but has developed a sinuous outline and is broken into 
a number of isolated areas. 

Structure and Thickness. 
The base of the Wicomico formation is so extensively covered with the 
Talbot formation which wraps about it that it is difficult to determine 
the attitude of the former by comparing the variovis heights at which 
its base is found to rest. A much more accurate conception may be 
secured by comparing the altitude of its surface in various places. In 
the northern part of the county the surface of the Wicomico formation, 
where it abuts against the margin of the Sunderland, rests at about 100 
feet, while at Eiclge, under similar conditions, it has an altitude of about 



92 THE GEOLOGY OF ST. MARY's COUNTY 

45 feet. These two locali'ties are separated by a distance of about 35 
miles, making an average slope toward the southwest of about 1.7 feet 
per mile. This attitude is largely due to the original slope which the 
surface of the forniatiou received wlion deposited, but in southern St. 
Mary's County an element of tilting seems to have brouglit the Wicomico 
lower than elsewhere in Maryland. 

The thickness of the Wicomico formation is variable, but averages 
about 20 feet. 

Character of Materials. 
The materials which .compose the Wicomico formation consist of 
clay, loam, sand, gravel, and ice-borne boulders. These, as a rule, do 
not lie in well-defined beds, but grade into each other both vertically 
and horizontally. The coarser materials, with the exception of ice- 
borne boulders, are usually found with a cross-bedded structure, while 
the clays and finer materials are either developed in lenses or are hori- 
zontally stratified. The ice-borne blocks are scattered throughout the 
formation and may occur in the gravel beneath or in the loam above. 
There is distinguishable throughout a tendency for the coarser materials 
to occupy the lower portions and the finer materials the upper portions 
of the formation, but the transition from the one to the other is not 
marked by an abrupt change. The coarser materials are frequently 
found above in the loam and finer materials belcw in the gravel, and are 
frequently much decayed. 

StratigrapJiic Relations. 
The Wicomico formation is deposited as a terrace lying unconformably 
and somewhat irregularly on the older beds of Eocene and Miocene age. 
This terrace was laid down about the margin of the Sunderland forma- 
tion and locally is believed to lap up on the thin eroded edges of the lat- 
ter, which are supposed to run out a short distance beneath it. It is 
everywhere separated from the Sunderland formation by a well-defined 
scarp, which is an ancient cliff cut by the waves of the Wicomico sea 
during the post-Sunderland depression. 



MARYLAND GEOLOGICAL SURVEY. 



ST. MARY'S COUNTY, PLATE VII. 








Fig. I. — VIEW showing Sunderland sltrface near great mills. 




Fig. 2. — VIEW showing sunderlaxd-wicomico scarp, wicomico surface in the fore- 
ground, near leonardtown. 



MARYLAND GEOLOGICAL SURVEY 



93 



Local Sections. 
The materials which compose the Wicomico formation vary rapidly 
from place to place. The following sections, however, will give an idea 
of the character of this formation: 



Pleistocene. 



Section at Drum CUff. 



Sandy clay 

Reddisb sand, loam, and gravel. 



Feet. 
5 
37 



Miocene. 



fossils 44 

86 

II. Section at Clifton Mills. 



Greenish sandy clay containin 
Total 



Feet. Inches. 



Pleistocene. 



Miocene. 



Reddish clay loam 1- 

Reddish sand and gravel somewhat decayed, carrying 

boulders as large as 1 foot in diameter 5 

Alternately drab clay and sand with iron crusts 15 

Obscure 



^ -B Sand, gravel, and boulders 15 

li a 1 Brownish sandy clay 1^ 

^•s — 

"^^ ^ Total 62 



THE TALBOT FORMATION. 

The Talbot formation has been named from Talbot County, Maryland, 
where it is extensively developed. In St. Mary's County it consists of a 
wave-built terrace composed of clay, loam, peat, sand, gravel, and ice- 
borne boulders, which have been deposited by the waves of Chesapeake 
Bay and its estuaries. The surface of the Talbot formation is coinci- 
dent with the lowest of the terrace surfaces described above. Since its 
deposition it has suffered less from erosion than either the Sunderland- 
or Wicomico formations. 

Areal Distribution. 
The Talbot formation is developed as a fringe about the margin of 
the Wicomico and occupies the lowest level of the three terraces. In 



94 THE GEOLOGY OF ST. :MARY's COUNTY 

the vallevs of the Patuxent and Potomac rivers, as well as in tlie de- 
pression of their principal tributaries, and along the liay sliorc, the 
Talbot formation is well developed. It is best seen, however, along 
the margin of the Potomac Eivcr, Avhere it occupies broad flats, par- 
ticularly on the peninsula between Wicomico Eiver and St. Clement 
Bay. Along the margin of the Patuxent River, between Horse Landing 
and St. Johns creeks, the Talbot, althoiigli present, has been reduced 
by erosion to a narrow belt scarcely separating the AA'^icomico on one 
side from the Eecent beach on the other. 

A large number of streams liave started to sink guillics in the body 
of the Talbot formation, but as yet have not developed extensive drain- 
age systems and the continuity of the deposit lias been, therefore, little 
affected by them. 

Structure and ThicJmess. 
The base of the Talbot formation ranges in elevation from a few 
feet above to a few feet below tide. There seems to be no general rule 
for this variation and it is apparently due to deposition on a slightly 
uneven surface. The highest portions of the surface of the Talbot 
formation are found around the margin, where it abuts against the 
Wicomico formation. In the northern part of the county tlie surface 
of the Talbot formation, where it abuts against the Wicomico, has an 
elevation of about 40 or 45 feet. This same elevation is continued 
southward to the vicinity of Town Creek on the Patuxent, and Breton 
Bay on the Potomac. From these localities it declines gently toward 
the southeast until at Scotland, near Point Lookout, the surface lies 
at a height of 10 feet. This gentle decline is probably due to a slight 
tilting in the direction of the Atlantic Ocean. The same feature has 
been described for the Wicomico and Sunderland formations in this 
region. The thickness of the Talbot formation is variable. Near 
Millstone a thickness of about 30 feet has been observed. In many 
other places the formation lias Ix'cii Found to thin down and disappear. 
Its average thickness is al)Out 1 5 foct. 



MARYLAND GEOLOGICAL SURVEY 95 

Character of Materials. 
The materials which compose the Talbot formation consist of clay, 
loam, peat, sand, gravel, and ice-borne boulders. These, as a rnle, do 
not lie in well-defined beds, but grade into each other both vertically and 
horizontally. The coarser materials, with the exception of ice-borne 
boulders, are usually foimd with a cross-bedded structure, while the 
clays and finer materials are either developed in lenses or are horizontally 
stratified. The ice-borne blocks are scattered throughout the formation 
and may occur in the gravel beneath or in the loam above. There is 
distinguishable throughout a tendency for the coarser materials to occupy 
the lower portions and the finer the upper portions of the formation, 
but the transition from one to the other is not marked by an abrupt 
change. The coarser materials are frequently found above in the loam 
and finer materials below in the gravel. They also show less decay than 
in the other surficial formations. Within the Talbot formation there 
are a number of lenses of drab clay, bearing plant remains. The most 
important of these are situated one mile north of Drum Point on the 
shore of the Patuxent Eiver, about a mile below the mouth of St. Leon- 
ard Creek. These have been discussed at length in the succeeding 
chapter. 

Stratigraphic Relations. 
The Talbot formation is deposited as a terrace lying unconformably 
and somewhat irregularly on the older beds of Eocene and Miocene age. 
This terrace was laid down about the margin of the Wicomico forma- 
tion and locally is believed to lap up on the thin eroded edges of the 
latter which are supposed to run out a short distance beneath it. It is 
usually separated from the Wicomico formation by a well-defined scarp, 
which is an ancient cliff cut by the waves of the Talbot sea during the 
post-Wicomico subsidence, but tliis relation is not always shown. 

^ Local Sections. 

The materials which compose the Talbot formation vary rapidly from 
place to place. The following sections, however, will give an idea of 
the character of this formation: 



96 



THE GEOLOGY OF ST. iMAKY S COUNTY 



« o 
Pleistocene. £ « . 



Miocene. 



I. Scclioii on Bay shore at Lanrjlcys Bluff. 



Sandy loam contaiuin?: scattered gravel. 

Coarse gravel 

Cross-bedded gravel and sand 

Fossiliferous greenish clay 

W'ry coarse gravel 



r 



Feet. Inches. 
3 






Fossiliferous sandy clay occurlng at beach level and 
extending downward to unknown depth 1 



Total 



23 



II. Section on Potomac Riirr at Wniles Bluff. 



*J o 

o 'z; 

Pleistocene. £ 2 -. 

« a 
^ 5? 



Sandy loam 

Sandy loam carrying gravel 

Cross-bedded sand and gravel 

Sandy clay carrying Ostrea and Venus 

Bluish clay, very fossiliferous, extending below tide. 

Total 



Feet. Inches. 
1 

3 G 

2 

4 



III. Section on I'otiminc Rirer heticecn Flood and Poplar Hill Creeks. 

Feet. 
^ g TSandy loam 1 



Pleistocene -^ ■§ J '■^^'^^'^^ ^^^ ^^^^ with ice-borne boulders 
■3 g 1 Gravel 



o 



o Dark clay bearing plant and invertebrate remains. ... 3 
Total 10 



Pleistocene. £ « , 

a S 

fa 



IV. Section ahnuj Potomac River 1.5 miles south of Sotterly Point. 

Feet. 

3 

3 

Dark drab clay carrying vegetable remains extending 
downward indefinitely beneath tide 2 



§ ''Sandy loam 

Cross-bedded white sand. 



Total 



THE RECENT DEPOSITS. 

The materials which constitute the Eecent deposits consist of mud, 
clay, sand, and gravel. These are deposited in deltas, flood plains and 
beaches, in the valleys of rivers and estuaries. The deposition of deltas 
and flood plains has been going rapidly forward, at least since the settle- 
ment of the country l)y Europeans. ]\Ien are still living who distinctly 



MARYLAND GEOLOGICAL SURVEY. 



ST. MARY'S COUNTY, PLATE VIII. 




Fig. I. — VIEW showing sllaekial erosion on sunderland-wicomico scarp, near 

LEONARDTOWN. 




Fig. 2. — VIEW showing section in WICOMICO formation near CLEMENTS. 



MARYLAND GEOLOGICAL SURVEY 97 

remember when vessels moored and discharged their cargoes in places 
which are now occupied by extensive marshes or meadow lands. Such 
deposition would doubtless not have occurred if the forests had 
been allowed to remain undisturbed, but the advent of the white man 
and the consequent destruction of the forests exposed the loose material, 
which forms the Coastal Plain, to the erosive effect of rain and rivers 
with the result that rapid denudation toward the headwaters of streams 
has been accompanied by rapid sedimentation along the lower courses. 
Many of the larger estuaries, such as the Patuxent and St. Mary's 
rivers and St. Jerome Creek, and St. Clement and Breton Bays, have been 
filled in toward their heads, while shorter estuaries have been trans- 
formed to meandering streams. The most extensive beach and dune 
deposits are found along the Bay and Potomac shores at Point Lookout 
and Sandy Point. Behind this obstruction, which separates the ocean 
waters of Chesapeake Bay from an ancient irregular shore line, lie many 
brackish water lagoons which have already been considerably filled up 
with sediment since they were separated from the Bay. 
• 

ORIGIN OF :\rATERIALS. 

The sources from which the Sunderland, Wicomico, and Talbot seas 
derived the materials for their respective deposits were principally con- 
fined to the Coastal Plain. The waves must have eroded large areas 
of the Cretaceous, Eocene, Miocene, and Lafayette and re-worked 
these materials into their own deposits. In addition to this, the Wicomico 
sea had the Sunderland deposits on which to erode and the Talbot sea 
had both the Sunderland and Wicomico land surfaces from Avhich to 
derive materials. Wlierever the Eocene sand and marls have been used 
in any considerable quantity, their presence is indicated by a peculiar 
greenish color imparted to the deposit. Miocene materials cannot be 
so readily detected, but they were, nevertheless, re-worked in large 
quantities. The rivers also brought in contributions from the Piedmont 
Plateau and the mountains of Western Maryland. This material was 
pushed along the bottom, drifted in suspension and floated along on 
ice-blocks. 



98 THE GEOLOGY OF ST. :MARY"s COUNTY 

Interpretation of the Geological Record, 
sedimentary record of the chesapeake group. 

The close of the Nanjemoy epoch was marked by an elevation of the 
region which brought the Eocene deposits above the ocean and exposed 
them to a prolonged attack of erosion. After the region had suffered 
extensively from the work of waves and rivers, it was again submerged 
beneath the ocean and the materials composing the Calvert formation 
were deposited. As the Miocene sea advanced little by little on the 
sinking surface of the mainland, the waves caught up and re-worked the 
clays and greensands of the various Eocene beds. The more obdurate 
fossils of the Eocene survived in a great measure the erosive work along 
the old Miocene shore and were carried out and deposited in deeper 
water. They may now be seen re-worked in the basal member of the 
Calvert formation. The old shore line of the Miocene sea which was 
formed during the Calvert epoch of sedimentation has nowhere been 
preserved in ]\Iaryland, but the materials which composed the Calvert 
formation in this county were deposited in seas of moderate depth in 
which an abundance of life was present, as is shown by the remains of 
diatoms and the extensive beds of fossil mollusks. The remains of 
whales and other cetaceans show that these vertebrates abounded in tlie 
ocean, and the discover}^ of a bone belonging to a gannet indicates that 
birds existed along the nearby shores. This particular form doubtless 
sought its food in the sea as the modern fishing gannets do at the present 
time. 

The Calvert epoch was brought to a close by the elevation of the I'egion 
once more above the level of the ocean. A period of erosion followed 
which was probably of short duration and closed with the depression of 
the region again beneath the sea. Then followed the deposition of the 
Choptank and St. Mary's formations, in which conditions similar to 
those just described for the Calvert were repeated. 

SEDIMENTARY RECORD OF THE LAFAYETTE FORMATION. 

At the close of the Miocene period St. Mary's County and adjoining 
areas were lifted al)ovo tlie ocean to I'onii Iniid. The full extent of 



MARYLAND GEOLOGICAL SURVEY 99 

the uplift is not definitely known, but it is certain that the sea retreated 
eastward considerably beyond its present shore-line. Stream erosion 
at once began to attack this new land area and to cut it down to base 
level, where it remained for a long time until the crystalline rocks of 
the Piedmont Plateau were decayed to a great depth below the surface. 
The rocks of complex mineralogical composition were reduced to quartz 
sand and a red clay, while the quartz veins were broken up and scattered 
as angular pebbles over the surface. When, at the beginning of the 
Lafayete period, this land mass was tilted so as to elevate the Piedmont 
and depress the Coastal Plain below ocean level, the waters of the 
Lafayette sea advanced over the sinking surface and streams gorged 
with detritus from the decayed, uplifted Piedmont above, rushed down 
to the sea and poured their contents into the ocean. Either the waves 
were weak or the sea advanced rapidly or this decayed material was 
discharged in enormous quantities, for the sea was unable to cope with 
the detritus poured into it and deposited it unsorted on the bottom. 
The amount of this depression is not known, but it is certain that the 
land was submerged to at least 500 feet below its present altitude. 

SEDIMEN^TARY RECORD OF THE COLUMBIA GROUP. 

The sedimentation of the Lafayette formation was brought to a close 
by the elevation of the region once more above the ocean. After an 
extensive interval of erosion, during which the depressions of the prin- 
cipal estuaries in the Coastal Plain were made, the country was again 
lowered beneath the waves, and the deposition of the formations belonging 
to the Columbia Group began. 

These formations, to which the names Sunderland, Wicomico, and 
Talbot have been applied, are developed in terraces lying one above the 
other in a vertical range from tide to an altitude of about 180 feet. 
Beneath these three terraces, there is forming to-day a fourth which 
extends from high-tide downwards beneath the waves. 

The key to their interpretation is secured by studying the manner in 
which this recent terrace is forming. At the present time the waves of 
the Atlantic Ocean and Chesapeake Bay are engaged in tearing away 



100 THE GEOLOGY OF ST. MARY'S COUNTY 

the land along their shores and in depositing the detritus on a submarine 
platform or terrace. This terrace is everywhere present and may be 
found not only along the exposed shores but also passing up the estuaries 
to their heads. The materials are extremely variable. Along the un- 
broken coast the detritus has a local character, while near river mouths, 
the terrace is composed of the debris contributed from the river basin. 

In addition to building a terrace, the waves of the Atlantic and the 
Chesapeake are cutting a sea-cliff along their coast line. The height of 
this cliff depends not only on the force of the breakers but also on the 
■ relief of the land against which the waves beat. A low coast line yields 
a low sea-cliff, and a bold coast line, a high one, and each passes into 
the other as often and as rapidly as the topography changes, so that as 
one travels along the shore of Chesapeake Bay high cliffs and low de- 
pressions are passed successively. The wave-built terraces and the wave- 
cut cliffs are important features along the entire extent of the Bay 
shore, and should be sought for wherever other terrace surfaces are 
studied. It must, however, be borne in mind that there are places 
along the Bay shore where the sea-cliff is absent, or so low that it does 
not form a conspicuous feature in the topography. In addition to these 
features, bars, spits, and other wave and current-built formations of a 
similar character are frequently met with. 

If the present coast line should be elevated, the submerged platform 
which is now forming would appear as a well-defined terrace of variable 
width with a surface sloping gently toward the water. This surface 
would fringe the entire Atlantic and Bay shores as well as those of all 
the estuaries. The sea-cliff would at first be sharp and easily distin- 
guished, but as time passed, the least conspicuous portions would gradu- 
ally yield to the levelling influences of erosion, and might gradually dis- 
appear altogether. Erosion would also destroy in large measure the 
original continuity of the formation, but as long as portions of it re- 
mained, the old surface could be reconstructed and the history of its origin 
determined. 

If the topographic and geologic features which are associated with the 
terrace now forming are compared with those which accompany the 



MARYLAND GEOLOGICAL SURVEY. 



ST. MARY'S COUNTY, PLATE IX. 




I'll,. I. — VIEW SHOWING THE FOSSIL BED IN THE TALBOT FORMATION AT WAILES BLUFF. 




i^lG. 2. — VIEW SHOWING THE FOSSIL BEIl IX THE TALDOT FORMATION AT WAILES BLUFF. 



MARYLAND GEOLOGICAL SURVEY 101 

various terraces of the Columbia group, the analogy is found to be so 
striking that the conclusion regarding a common origin of both is irre- 
sistible, and there can be no reasonable doubt that the mode of formation 
of the modern terrace furnishes the key to the interpretation of the 
ancient. 

The subsidence of the Atlantic Coastal Plain, which carried down 
beneath the ocean level the entire surface of St. Mary's County, gave 
opportunity for the waves to finish the destruction of such portions of 
the Lafayette formation as chanced to survive the erosive work of the 
streams. As St. Mary's County sank slowly beneath the water, the 
shore of the advancing i^tlantic gradually worked further and further 
landward until it finally came to rest near Charlotte Hall. St. Mary's 
County at that time was being rapidly covered by an off-shore deposit 
of mud, sand and gravel. How long the sea remained in this position 
is not definitely known, but it is certain that it remained long enough 
for the waves of the Sunderland sea to cut a well pronounced scarp-line 
against the Lafayette. These ancient sea cliffs are to-day prominent 
features of the topography of southern Maryland and may be mapped 
as easily as the sea cliff which is now being cut by the waves of Chesapeake 
Bay and its estuaries. 

While the Sunderland off-shore deposits were still in process of forma- 
tion over the surface of St. Mary's County, the region rose again above 
the surface of the water and erosion began vigorously to cut away the 
loose sands and gravels which had been deposited just before. How 
extensive this uplift was, it is now quite impossible to say. It is equally 
difficult to determine its duration, but it was of sufficient length to 
permit the destruction of a large portion of this Sunderland formation, 
for many of the larger streams within St. Mary's County opened up deep 
valleys within it. 

The question as to whether the Patuxent Eiver first came into exist- 
ence at this point or previously in the erosive interval which followed 
the uplift of the Lafayete formation has been discussed elsewhere in 
this volume. 

After St. Mary's County had been subjected to erosion for a certain 



102 THE GEOLOGY OF ST. MARY'S COUNTY 

period, it was again submerged, but not to the same extent as in the 
previous cycle, during the deposition of tlie Sunderland formation. 
The subsidence, however, was sufficient to drown the rivers which 
liad opened up their valleys across the county and to transform these 
into estuaries, so tliat n waterway extended across Calvert County 
from what is now the mouth of Fishing Creek to the mouth of Hunting 
Creek. Another waterway from the south ran from Drum Point south- 
westward to what is now the head of the Hunting Creek estuary, and a 
third extended from what is now the mouth of Parker Creek across tlie 
divide to Battle Creek. Other streams of less importance were also trans- 
formed into estuaries, so that the county presented a most irregular 
shore line and the lower half of the region was transformed into a group 
of small irregular islands. The subsidence at this time amounted to 
about 90 feet. x\s the region remained at tliis level for some little 
time, the waves along the shore had an opportunity to do considerable 
erosive work and forced the shore lines back toward the rivers, widening 
the valleys which had been previously opened during the erosive interval 
which followed the uplift of the Sunderland formation. The material 
which was derived from the wave erosion was deposited along the floor 
of these estuaries, filling them in to a considerable extent and raising 
them up to a higher level than that which they possessed when the 
country was submerged at the beginning of the epoch. While this pro- 
cess of sedimentation Avas still in progress, the country once more rose 
above the level of the waves and permrtted the streams to cut again in 
their old valleys. This epoch of elevation was apparently a short one 
for there was not enough time to enable the streams to completely re- 
establish themselves throughout the entire length of their former valleys. 
They had only partially begun the erosive work when the country was 
once more submerged beneath the waves and the deposition of the Talbot 
terrace was begun. At this time, the streams were once more transformed 
into estuaries, but not to the extent which they were in the previous 
Wicomico cj'cle of deposition. The land did not sink more than 15 feet 
below its present altitude and remained there for only a short time when it 
was once more raised and eroded. This epoch of elevation was the one 



MARYLAND GEOLOGICAL SURVEY 103 

which ushered in the present cycle of events and permitted the cutting 
of the Recent sea-cliff. Since its initiation, the land has once more as- 
sumed a downward motion, and the entire coast line in this region seems 
to be sinking once more beneath the level of the waves. 

Along the shore of Chesapeake Bay and the lower courses of many 
of its estuaries there occur at intervals deposits of greenish-blue clay 
developed as lenses in the body of the Talbot formation. Usually the 
base of the clay is not visible but its stratigraphic relations are such as 
to leave no doubt that it, or a thin gravel bed on which it occasionally 
rests, is uncomformable on whatever lies beneath. The upper surface 
of these clay lenses is everywhere abruptly terminated by a bed of coarse 
sand or gravel which grades upwards into loam and at its contact with 
the clay strongly suggests an unconformity. These clay lenses are in 
some localities devoid of fossils but in others they contain remains of 
marine and estuarine animals and land plants. Many localities for these 
clays are already known and as exploration advances new ones are fre- 
quently discovered. Some of the more typical exposures will now be 
described. 

Along the shore, about a mile below Bodkin Point, Anne Arundel 
County, the variegated clays of the Earitan formation are finely exposed 
in a cliff some 30 feet in height. These clays occupy the greater portion 
of the section and carry an abundance of lignite more or less incrusted 
with crystals of pyrite. Sands and gravels of the Talbot formation un- 
conformably overlie the clays and constitute the upper portion of the cliff. 
Half a mile farther south the cliff still maintains its former height, but 
the section has changed. Some ancient stream must have established its 
valley on the Earitan, for here the surface of that formation, like a great 
concave depression, passes gradually beneath the beach to appear again 
in the cliff 150 yards to the south. In this hollow, lying unconformably 
on the Earitan formation, is a bed of dark-colored clay about 15 feet 
thick. Bluish and greenish tinted bands of clay relieve somewhat its 
somber aspect, and at about its middle portion it carries a bed of peat. 
But its most striking feature is the presence of huge fossil cypress knees 
and stumps which are imbedded in its lower portion. These stumps 



lOi THE GEOLOGY OF ST. MAKY's COUNTY 

vary in diameter from 2 to over 10 feet, and after the removal of tlie 
surrounding clay, stand out prominently in tlie position in which they 
must have grown. Mr. A. Bibbins, to whom the author is indebted for 
notes on these deposits, has counted 32 of these stumps which were 
visible at one time, and also reports finding worm-eaten beechnuts inti- 
mately associated with cypress cones near the base of the formation. 
Sands and gravels of the Talbot formation overlie the whole. Imme- 
diately south of this outcrop the dark-colored clays are temporarily re- 
placed by the Earitan formation, but they appear again a little farther 
down the shore, and afford an almost unbroken exposure for about a mile. 
The thickness of the clay in this locality is at first about 10 or 12 feet, 
but it gradually becomes thinner southward and finally disappears alto- 
gether. Casts of Unio shells and not vegetable remains, are its pre- 
dominant fossils, while, like the beds containing the cypress swamp, it 
overlies the Earitan formation unconformably, and is itself abruptly 
buried beneath Talbot sands and gravel. 

Another locality is on the Bay shore, about a mile northeast of Drum 
Point. Here, at the base of a cliff about 30 feet high, is a 2-foot bed 
of dark, chocolate-colored clay carrying gnarled and twisted sticks pro- 
truding in every direction from the material in which they are imbedded. 
Above this occurs a thin seam of lignite 1^ feet thick, which in turn is 
overlain with about 5 feet of slate-colored clay. At this point the con- 
tinuity of the deposit is interrupted by a series of sands, clays, and 
gravels belonging to the Talbot formation, which extend upward to the 
top of the cliff. Although the base of this lignitic clay series is buried 
beneath beach sands, field relations lead to the conclusion that the de- 
posit is very much younger than the Miocene clays on which it rests un- 
conformably. A similar section is to be seen on the Patuxent Eiver, 
about a mile below Sollers Landing. Large stumps here protrude from 
a dark, basal clay bed, some 5 feet in thickness, which is covered by 3 
feet of sand, and this again is buried beneath 10 feet of Talbot sand 
and gravel. The relations of the basal clay to the underlying Miocene 
is again obscure, but indications point to an unconformity. Another 
section is exposed along the shore 1^ miles northwest of Cedar Point, 



MARYLAND GEOLOGICAL SURVEY. 



ST. MARY'S COUNTY, PLATE X. 




CHARACTERISTIC FOSSILS OF THE PLEISTOCENE OF ST. MARY S COUNTY. 



1. Ilyanassa obsoleta (Say) Dall. 

2. EuPLEURA CAUDATA (Say) Holines. ^ 

3. PoLYNiCES (Neverita) duplicatus (Say) DaU. 

4. FuLGUR canaliculatum (Linne). 

5. HicoRiA glabra (Mill) Britton. 

6. 7. Corbula contracta Say. 

8. Tagelus gibbus (Spengler) Dall. 



y. Rangia cuneata (Gray) Dall. 

10. Arca (Noetia) ponderosa Say. 

11. Mya arenaria Linne. 

12. Barnea (Scobina) costata (Lmne) Dall. 
13 OsTREA viRGiNicA GmcHn. 

14. Tooth of Mastodon, Mammut americanum 
(Kerr) (greatly reduced). 



MARYLAND GEOLOGICAL SURVEY 105 

where a thin bed of drab clay carrying vegetable remains is overlain 
abruptly with sands and gravels. Its contact with the Miocene is again 
unfortunately obscure. At the localities just described no animal re- 
mains have been discovered, but on the north bank of the Potomac, about 
half way between St. Mary's Eiver and Breton Bay, there is a deposit of 
lead-colored clay, exposed for a quarter of a mile along the shore. It is 
buried at each end as well as above by sands and gravels and carries both 
lignite and Rangia cuneata (Conrad). Although the description given 
by Conrad is somewhat vague, it is highly probable that he visited this 
locality and collected specimens of the fossils. Two more localities 
still remain to be mentioned. Cornfield Harbor, and its companion de- 
posit exposed 5^ miles south of Cedar Point on the Bay shore. Conrad 
was well acquainted with these deposits and to the former he devoted 
special attention. Each is about 10 feet thick, occurs at the base of a 
low cliff, is composed mostly of a dark, lead-colored clay, and is overlain 
abruptly with Talbot sand and gravel, while unconformity on the Miocene 
is beautifully shown at the base of the Bay shore section. A number of 
fossils have been described from the Cornfield Harbor locality, among 
which are Ostrea virginica Gmelin, Area ponderosa Say, Area transversa 
Say, Venus mereenaria Linne, Mya arenaria Linne, Barnea costata 
(Linne), Crepidula plana Say, Polynices duplicatus (Say), and Fulgur 
cariea (Gmelin). In this exposure the lower 4 feet of clay carries the 
marine forms and above this there are 2 feet of sandy clay literally packed 
with Ostrea virginica. These same general relations hold for the similar 
deposits south of Cedar Point. 

.^ The stratigraphic relation of these lenses of clay which are surely 
unconformable on the underlying formation and apparently so with the 
overlying sand and loams of the Talbot formation is a problem which 
engaged the attention of the author until it appeared that the apparent 
unconformity with the Talbot, althougli in a sense real, does not, how- 
ever, represent an appreciable lapse of time and that therefore the clay 
lenses are actually a part of that formation. In order to understand 
more clearly what is believed to have taken place, these clay deposits 
should be divided into two groups, those which carry plant remains con- 



106 



THE GEOLOGY OF ST. MARY S COLNTY 



stitnting one, and those containing marine and brackish-water fossils 
the other. Such as are devoid of fossils may belong to either one of the 
groups according to their situation but probably more frequently belong 
to the latter. 

In a word, the clays carrying plant remains are regarded as lagoon 
deposits made in ponded stream-channels and gradually buried beneath 
the advancing beach of the Talbot sea. The clays carrying marine and 




Fig. 5. — Diagram showing pre-Talbot valley. 

brackish-watcr organisms are believed to have been at first off-shore 
deposits made in moderately deep water and later brackish-water de- 
posits made behind a barrier-beach and gradually buried by the advance 
of that beach toward the land. Taking up the first class of deposits in 
more detail they are believed to have been formed in the following 
manner : 

During the erosion interval which immediately preceded the deposition 
of the Talbot formation many streams cut moderately deep channels in 
the land surface, which on the sinking of the region again were trans- 



MARYLAND GEOLOGICAL SURVEY 



107 



formed into estuaries (Fig. 5). Across the mouths of the smaller oi 
these drowned valleys the shore currents of the Talbot sea rapidly built 
bars and beaches which ponded the waters behind them and transformed 
them from brackish-water estuaries to fresh-water lagoons. These la- 
goons, however, were gradually changed into marshes and possibly to 
meadows by the inflow of detritus from the surrounding region and on 
the new land surface thus formed various kinds of vegetation took up 




Fig. 6.— Diagram showing advancing Talbot shore-line and ponded stream. 



their abode (Fig. 6). At first the beach-sands advanced in the lagoon 
and filled up completely that portion of the submerged trough which 
lay immediately beneath them, but later, as the lagoon was silted up 
more and more with mud derived from the surrounding basin, the ad- 
vancing beach came to rest on this lagoon deposit as a foundation and 
arrived at length at the point where the lagoon had been filled up to 
the level of wave-base or higher. When this place was reached another 
process was added to that of beach advance. Heretofore the waves and 
wind had been simply pushing forward material over the advancing front 



108 



THK GEOLOGY OF ST. .MAHY S COLNTY 



but now the mud deposit in the lagoon had actually reached the level of 
wave-work and had transformed the lagoon from a pond to a marsh or to 
a meadow, the breakers attacked the upper portion of the lagoon deposit 
and eroded it down to the level of wave-base as rapidly as they could 
reach it from under the superficial veneer of tlie beach-sands. Cypress, 
cat-tails, sedges, and other vegetation which had taken up their abode 
in the marsh would be overwhelmed with detritus by the advancing beach 




Fig. 7. — Diagram showing later stage in advance of Talbot shore-line. 

and a little later be destroyed by the breakers. In this way all traces 
of life must be removed from the deposit except such as happened to 
occupy a position lower than wave-base. One, therefore, finds preserved 
in the clay water-logged trunks and leaves, nuts, etc., and roots of huge 
trees like the cypress. The area over which the waves had removed the 
upper portions of the lagoon deposit can be determined not only by the 
presence of truncated stumps but also by the character of the contact. 
Here there is a sharp division between the clay and tlie overlying sand 
and gravel while the area over wliich the beach advanced without cutting 



MARYLAND GEOLOGICAL SURVEY. 



ST. MARY'S COUNTY, PLATE XI. 




^ ■ ■■■^■- 



1-1(,. 1. \IE\\ SHi)\\IX(; SWAMP I.AXll NKAK UXlLE. 




'<^ak 




Fig. 2. — VIEW showing barrier beach xear millstone. 



MARYLAND GEOLOGICAL SURVEY 



109 



would be indicated by a partial mingling of the beach material with 
lagoon mud. 

A still later stage in the process is illustrated in the accompanying 
diagram (Fig. 7) which represents a stage where the waves have so far 
advanced as to largely destroy the original stream channel. A small 
portion of the old lagoon still exists at the head of the swamp but its 
lower portions have long since been submerged and covered over by the 
advancing beach. The transverse section shows what is left of the 
lagoon deposits of mud carrying truncated stumps of cypress and other 
trees which happened to be buried deep enough to escape the destructive 
powers of the breakers. The broken line indicates the outline of the clay 
lens. Fig. 8 is a section through the same region made at right angles 




Fig. 8. — Ideal section showing advance of Talbot shore-line. 



to the one just described. At D the breakers are forcing forward the 
beach upon the meadow. Just off from the beach the waves have swept 
away the sand and are eroding on the lagoon mud which reached out to 
them under the beach veneer. At G the waves have succeeded in cutting 
down the lagoon deposit to wave-base and have left behind a thin veneer 
of sand and gravel as the sinking land carries it below the reach of the 
waves. At B the lagoon deposit was not thick enough to reach the zone 
of wave-erosion and simply grades up into a thick deposit of sand and 
loam which passes out toward A. 

The second category of clay lenses, namely those carrying marine and 
brackish-water organisms are understood to have been formed in a 
somewhat different manner. The lower portion carrying the marine 
organisms points to salt-water conditions and contains remains of sea 
animals which live to-day along the Atlantic coast. At the time when 



110 Till-: (;i:()i.()GY of st. mart's county 

this deposit was formed, the ocean waters had free access to the region 
and tlie bhie nuid in which they are now imbedded and in which they 
lived was a quiet-water deposit laid down some distance from the land 
Later, however, it would appear that a barrier beach was constructed 
shutting off a portion of the sea-bed which had formerly been occupied 
by marine animals and gradually allowing it to be transformed from 
salt-water conditions to those of brackish water. In this brackish-water 
lagoon the fauna changed to that found along our estuaries to-day and 
huge oysters flourished and left behind them a deposit of shell-rock. 
With the bar advancing landward this lagoon was gradually filled up 
with sand and gravel and finally obliterated. 

The upper unconformity, then, in the case of the fresh-water and the 
brackish-water lagoons is real only in the sense that an unconformity in 
a cross-bedded wave- and delta-deposit is real. There is, it is true, a lack 
of harmony in the position of the beds and a sharp break is indicated 
but there is no indication of an appreciable time-lapse between the 
clay and the oyster-bed on the one hand and the overlying sands and 
gravel on the other, and the sea which eroded the clay to a fixed level 
immediately afterwards overspread the surface of the same with a veneer 
of beach sand. There is, therefore, no time break indicated by this 
unconformity and the lenses of swamp-clay as well as those carrying 
marine and brackish-water organisms are to be looked upon not as 
records of elevation and subaerial erosion but as entombed lagoon- 
deposits made in an advancing sea and contemporaneous with the other 
portions of the formation in whose body they are found. 

The hypothesis here advanced is based on and reinforced by many 
observations along the present shores of the Atlantic Ocean, Chesapeake 
Bay, and its estuaries. Each step in the process described above is there 
illustrated and some of them are met with again and again. 

As one passes along the shores of Chesapeake Bay and of the rivers which 
flow into it, stream channels are continually met which have arrived at 
more or less advanced stages in the above-mentioned process. Some are 
in part converted into lagoons, by bars built across their mouths, others 
show partial filling by mud washed in from the surrounding country, 



MARYLAND GEOLOGICAL SURVEY 111 

and still others have i-cached the advanced stage of swamps or meadows 
in which various t3'pes of vegetation are flourishing. In addition to the 
usual undergrowth which is found in wet places, the cypress has taken 
up its abode in these bogs and has converted some of them into cypress 
swamps. For great stretches along the shore the advance of the sea is 
indicated by well-washed clitfs while in other places the waves are found 
devouring beds of clay which are situated immediately in front of lagoon 
swamps and separated therefrom by nothing hut a low superficial beach. 
These clay beds invariably lie at and below water-level, are very youuii' 
in age, and evidently pass directly under the beach to connect with the 
lagoon-clay beyond. This interpretation is made the more certain by 
the presence of roots in the wave-swept clays which but a short time 
before belonged to living plants identical with those now flourishing 
behind the beach, and point to a time not far distant when they also 
were a part of the lagoon swamp behind a beach situated a little farther 
seaward. At Chesapeake Beach a ditch has been cut through one of 
these beaches which shows a continuous deposit of clay from a lagoon 
swamp passing out under the beach to the Bay beyond. The waves are 
thus caught, as it were, in the act of eroding the upper portion of the 
lagoon deposit. 

From a large body of data gained from over a wide area, it is evident 
that the erosion which occurred during the interval between the eleva- 
tion of the Talbot terrace and the present subsidence of the coast was 
sufficient to permit streams to cut moderately deep valleys in the former. 
It would then appear that as the region was gradually lowered again 
beneath the present ocean the upper portions of the stream-channel in 
time passed below wave-base and whatever has collected in them since 
that period will be preserved beneath the advancing sea as a more or 
less fossiliferous clay lens apparently unconformable beneath beach 
debris. 

The barrier beaches which exist at intervals along the Atlantic coast 
of N"ew Jersey, Delaware, Maryland, Virginia, and southward show us 
how portions of the ocean-bed, which were formerly bathed by salt water 
and sustained a marine fauna, are now converted to lagoons behind 



112 THE GEOLOGY OF ST. MARY S COUNTY 

barrier beaches, and have passed over in varying degrees to brackish- 
water conditions bearing estuarine faunas. 

Similar deposits to those just described have been seen by the author 
along the Eappaliannock River, especially at Mosquito Point, and there 
is no reason to doubt that they occur in many other places along Chesa- 
peake Bay and its estuaries, within the State of Virginia. From analogy, 
it would be expected that similar deposits would be discovered along 
Delaware Bay where conditions must have been identical with those which 
prevailed in Chesapeake Bay. That such deposits do occur along the 
shores of the Delaware there can be no doubt. The most noted of these 
is at Fish House on the New Jersey side of the Delaware Eiver a few 
miles above Philadelphia. 



MARYLAND GEOLOGICAL SURVEY. 



ST. MARY'S COUNTY, PLATE XII. 




Fig. I. — VIEW of st. jerome creek .showing drowned valleys near ridge. 




Fig'. 2. — VIEW of breton bay from abells wharf. 



THE ECONOMIC RESOURCES OF ST. MARY'S 

COUNTY 



BY 

BENJAMIN L. MILLER 



Introductory. 

The economic resources of St. Mary's County are neither varied nor 
especially valuable yet several of them are worthy of more attention than 
they have thus far received. Aside from the soils, which are foremost 
in importance and value and which are discussed in a subsequent chapter, 
the county contains several deposits of considerable economic value, none 
of which are, at present, utilized to their fullest extent. These are 
the clays, sands, gravels, glauconitic and shell marls, and diatomaceous 
earth. In addition, valuable water resources contribute much to the 
mineral wealth of the region. 

Almost all of these products have an especial value to the residents 
of the county in that they either contain ingredients for soil enrichment 
or materials for the construction of good roads. Since agriculture is 
the chief occupation it is believed that the general recognition of the 
value of the natural products of the region will lead to their greater 
use. This would eventually enhance farm lands through increased soil 
fertility and easier land transportation. 

The Natural Deposits. 

the clays. 

The clays constitute the most valuable economic deposits of the region. 

Every geologic formation represented in the county contains argillaceous 

strata, even though, in general, the deposits are composed principally of 

sand. The argillaceous beds are quite generally distributed throughout 



Ill THE ECOXO-MIC RESOURCES OF ST. MARY's COUNTY 

the region and, in a few instances, liave furnished materials for the 
manufacture of hrick. The}' are not suitable for pottery or the finer 
grades of brick but make a fairly good variety of common red brick. 
Since the clay supplies are ample there seems to be no good reason why 
the county should not produce all the brick and tile of this character 
required for local uses. Should a ready market be found and better 
means of transportation obtained, brick for shipment might perhaps be 
produced at a profit. However, since other counties in the State more 
favorably situated with respect to markets and the main lines of railroads 
contain equally extensive clay deposits, sometimes of a better quality, it 
is not probable that St. Mary's County will ever become an important 
clay center. It should, however, produce enough brick to supply the 
local demand. 

Should the experiments that are being tried elsewhere of using burned 
clay for road metal prove to be successful some of the clay of the county 
may be profitably used in this way. Since the sandy roads seriously 
interfere with the development of the region there will undoubtedly be 
an increased demand, sooner or later, for cheap road metal, and it is 
possible that the clay of this region may partially meet this demand. 
The clays occur in deposits of both Tertiary and Quaternary age. 

Tertiary Claims. — Although argillaceous beds occur very frequently 
in the Miocene and Lafayette strata of the State, in general they are too 
sandy to be of much economic importance. 

The Calvert, Choptank, and St. Mary's formations of the Miocene all 
contain beds of sandy clay which are well exposed in many places along 
the Patuxent Eiver and in the other stream valleys. The Calvert, which 
outcrops in the northwestern portion of the count}', contains more of this 
clay than do the other Miocene formations, and the clay is less sandy. 
It is bluish-green to black when fresh, but becomes lighter in color on 
exposure. It has never been worked and is probably of little economic 
value because of its large percentage of sand, iron, and lime. The lijue 
is derived from the numerous fossil shells which are either generally 
distributed throughout the sandy clay or massed in definite shell beds 
within it. 



MARYLAND GEOLOGICAL SURVEY 115 

The Lafayette formation, which is represented in this county by 
several small outliers in the vicinity of Charlotte Hall, usually contains 
a surface capping of clay loam which, elsewhere in the Coastal Plain, 
has been quite extensively used for brick. However, in this region, its 
small areal extent renders it of little value. 

Quaternary Clays. — The clays of the post-Lafayette of the county 
greatly exceed in value those of the underlying deposits and are 
found in each of the three Pleistocene members. Their mode of occur- 
rence is very similar in the different formations as is also their general 
character. The clays occur in the form of a surface capping of clay 
loam representing the last stage of deposition in each epoch, and as lenses 
of light drab to dark brown clay contained in the body of the deposits. 
In all probability the surface loam was not everywhere developed and 
often where it was once present it has since been removed by erosion, so 
that it is by no means co-extensive with the various Pleistocene forma- 
tions of whicli it forms a part. It is extremely variable in thickness, 
ranging from a few inches to 6 or 8 feet in St. Mary's County, while in 
other parts of the Coastal Plain it is often much thicker. 

The Sunderland formation contains a greater development of clay 
loam than it does in Calvert County, and for this reason the upland roads 
which are generally located on the Sunderland-covered divides are less 
sandy than in Calvert County. The clay loam of the Sunderland con- 
stitutes the greater portion of the Leonardtown and ISTorfolk loams, 
whose distribution is shown on the soil map of the county. In many 
places the materials mapped as loam are entirely too sandy for the 
manufacture of brick, but in many other places in these areas clay 
suitable for common brick can be obtained. Where the clay caui be 
used the cost of removal entails only a slight expense because of the 
small amount of stripping required. Similar clays, utilized in Virginia 
are obtained by merely removing the few inches of surface material 
which is tilled with plant roots. 

Beside the surface clay loams, lenses of plastic drab clay are fre- 
quently found near the base of the Sunderland deposits. These can be 
seen outcropping in many places on the steeper slopes. In general, 



116 THE ECONOMIC HESOUUCES OF ST. MAKY's COLNTY 

these lenses are of small extent but some are sufficiently thick and 
extensive to be worked, althougli in places they contain considerable 
ve^Tetable material which renders them less serviceable. 

The clays of the Wicomico formation closely resemble those of the 
Sunderland both in general character and mode of occurrence. The 
surface loams in many places are suitable for the manufacture of a fair 
quality of brick, although they have never been used for that purpose 
in the county. Elsewhere in the State and in adjoining States extensive 
brick plants obtain their material from the surface clay loam of the 
Wicomico formation. In a general way the areas of Sassafras loam shown 
on the soil map of the county approximately represent the development 
of the Wicomico surface loams. It must be borne in mind, however, 
that a soil map and a geological map are constructed on an entirely 
different basis and seldom do the lines defining the areas of certain soils 
coincide with the boundary lines of the geological formations. Some 
small portions of the Sassafras loam are of Sunderland age and some 
belong to the Miocene yet the greater part represents the Wicomico 
surface loam. Further small portions of the Wicomico sui'face loam 
are mapped as meadow soils on the soil map. The clay lenses of the 
Wicomico which resemble those of the Sunderland are not extensive 
enough to be of any particular importance. 

The loam cap of the Talbot is more persistent than is that of the 
Wicomico and Sunderland formations, and is almost co-extensive with the 
distribution of the Talbot formation in this county. Just across the 
Patuxent Eiver, in Calvert Count}', near Solomon's Island, brick was 
formerly made from the Talbot clay loam. In St. Mary's County these 
Talbot loam areas are most extensive along the Potomac Eiver, where 
they cover the low, flat divides between the tributary streams. With 
the exception of the valleys of the smaller streams the meadow soil 
areas of the soil map approximately coincide with the distribution of 
the Talbot surface clay loam. As has been demonstrated by the brick 
plant in Calvert County, the Talbot loam produces a fair quality of 
brick. 

Beside the surface loam of the Talbot, there are several other deposits 



MARYLAND GEOLOGICAL SURVEY 117 

of cla3^ present in this formation which doubtless have some vahie. They 
consist of lenses of bluish-green to black plastic clay which have been 
exposed through wave-cutting along the Bay and the Potomac Eiver in 
the southern portion of the county. The best exposures of this material 
occur along the Bay shore about 5 miles south of Cedar Point, at Wailes 
Bluff, along the Potomac Kiver, about 1 mile north of Cornfield Point, 
and on the east shore of Breton Bay, about one-fourth mile below 
Lovers Point. Similar clays occurring at Bodkin Point near the mouth 
of the Patapsco Eiver have been tested and described by Dr. Heinrich 
Eies.^ He states that the clay " burned to a good red color under 
ordinary conditions and to a deep brown when vitrified. Before this 
clay could be used in large ware it would be necessary to add sand to 
prevent excessive shrinkage." In certain outcrops these clays contain 
sufficient vegetable material to render them unfit for use but in others 
they contain very little organic matter. 

THE SANDS. 

Since the arenaceous phase predominates in almost every formation 
represented in the region, the county contains an unlimited supply of 
sand. The sand of the Pleistocene is used locally for building purposes, 
but since it is so readily obtained in all parts of the county no pits of 
any considerable size have been opened. It is said to be a fairly good 
building sand yet no better than quantities of sands in other parts of the 
State, hence the demand for it is purely local. 

In some places the quartz sands of the Miocene seem to be pure enough 
for glass-making, suggesting the ]\Iiocene glass sands so extensively ex- 
ploited in southern New Jersey, although tliey have never been used for 
that purpose in this region. Careful chemical analyses and physical 
tests, which have not been made, would be required to determine their 
usefulness in this respect. 

Locally, the Pleistocene sands are rich in ferruginous matter which, 
in places, cements the grains together forming a ferruginous sandstone. 

^Md. Geol. Survej^ vol. iv, 1902. 



lis THE ECONOMIC RESOURCES OF ST. MARYS COUNTY 

Sands of this character possess a distinct value for road-making pur- 
poses, as they pack readily and make a firm road bed. Where the 
material can be easily obtained in large- quantities good roads of this 
kind can be very economically constructed. The ferruginous sands are 
best developed in the Sunderland formation, principally because of the 
greater age of the deposits, altliough also represented in the Wicomico 
and the Talbot. 

THE GRAVELS. 

The Pleistocene formations contain numerous beds of gravel widely 
distributed throughout the region. They occur in pockets or lenses, 
either immediately at the surface or but thinly covered by the sands and 
loam. In the latter case they can be seen in many places outcropping 
along the valleys. These gravel deposits have only been used to a small 
extent in this section although similar deposits in the vicinity of Wash- 
ington have been extensively worked. As ballast for roads they possess 
considerable value and will doubtless be extensively used in the future 
in the building of permanent roads throughout the county. They are 
probably inferior in value to the igneous rocks yet serve their purpose 
well when properly used. They are generally ricli in iron, which acts 
as a cementing agent, although tliere arc many places where the gravels 
lack this desirable material. In such cases it is necessary to add ferru- 
ginous sand or clay to bind them together. The gravels range in size 
from coarse sand to pebbles several inches in diameter. They are 
especially well developed at the base of the Sundcrlaiul formntiou and 
are exposed in almost every place where streams have cut through the 
overlying loam and sand. Many of these outcrops of Sunderland gravels 
arc represented in the soil map as the Susquehanna Gravel areas. 

THE BUILDING STONE. 

Although the formations of tlie county are composed almost entirely 
of unconsolidated materials, yet locally indurated beds are not uncom- 
mon. In the absence of any better stone these indurated ledges furnish 
considerable material for the construction of foundations and well walls. 



MARYLAND GEOLOGICAL SURVEY 119 

At Sotterly Wharf, on the Patuxent Eiver, there is a firm ledge of 
Miocene rock which has been used for such purposes. Elsewhere ferru- 
ginous sandstones and conglomerates from the Pleistocene deposits 
supply the small local demand for rough building stones. 

THE MARLS. 

Extensive deposits of shell marl have a wide distribution throughout 
the Atlantic Coastal Plain and have been worked, at intervals, since 
the early part of the last century, when their value as fertilizers was first 
determined. However, their importance in the enrichment of soils de- 
ficient in lime has never been generally recognized. At present then- 
use in Maryland has been almost entirely discontinued, although the 
deposits are practically inexhaustible. At the Xomini Cliffs, just across 
the Potomac Eiver, in Virginia, shell marl has been dug for shipment 
and used in the manufacture of artificial fertilizers. 

The Calvert, Choptank, and St. Mary's formations all contain beds 
of shell marl which are exposed in the river cliffs and valley slopes in 
many places throughout the county. The Talbot also contains deposits 
of shell marl at Langleys Bluff, on Chesapeake Bay, about 5 miles 
south of Cedar Point, and at Wailes Bluff, on the Potomac, about 1 
mile above Cornfield Point. The shell beds of the Choptank are the 
most important and are particularly well exposed at Drum Cliff, on 
the Patuxent Eiver. In places the shells are mixed with so much sand 
that the lime forms only a small percentage, but in other places the 
amount of lime exceeds 90 per cent. 

The value of the shell marls and methods for using them are thor- 
oughly discussed by Professor H. J. Patterson in a Bulletin of the 
Maryland Agricultural Experiment Station (No. 66, May, 1900). He 
states that the lime has an especially beneficial effect upon sandy soils, 
such as prevail throughout St. Mary's County, in improving their physical 
characteristics. This it does through its cementing action which ren- 
ders such soils less porous and thus enables them to retain moisture 
better. Chemically, lime corrects the acidity of the soils through its 
neutralizing effect upon acids, acting upon other soil constituents, ren- 



120 THE ECONOMIC RESOURCES OF ST. MARYS COUNTY 

dering them available for plant food, and finally serves as a plant food 
itself. ]Many experiments wliich have been tried in various places all 
show the value of lime as a fertilizer, and experiments in this State show 
that better results were obtained by the use of shell marl than with 
burned-stone lime. No doubt, any of the soils of Calvert County might 
be considerably improved at small expense by the generous use of shell 
marl, deposits of which are readily accessible to a large part of the 
county. 

THE DIATOMACEOUS EARTH. 

Diatomaceous earth, infusorial earth, or tripoli is a siliceous deposit 
coinposed mainly of the microscopic tests of diatoms, a low order of 
aquatic plants. The material is soft, porous, light in weight, and very 
friable. When fresh it is greenish in color but on exposure to the air 
the color changes to buff or almost pure white. The diatomaceous earth 
occurs in the lower part of the Calvert formation and is well exposed in 
many places along the Bay and river shores and in the tributary stream 
valleys in the northwestern portion of the county. 

The diatomaceous earth, on account of its porosity and compactness, 
is used in water filters. It is reduced readily to a fine powder and makes 
an excellent base for polishing powders. On account of its porous 
nature, diatomaceous earth is used as an absorbent in the manufacture 
of dynamite, while its non-conductivity of heat makes it a valuable in- 
gredient in packing for steam boilers and pipes, and in safes. This 
latter is the principal use to which it is put. It has been thought that 
the diatomaceous earth might be of use in certain branches of pottery 
manufacture, which require on the part of the materials refractoriness 
and an absence of color when burned. Dr. Ileinrich Ries tested a sample 
of the diatomaceous earth from Lyons Creek at cone 27 in the Deville 
furnace and found that the material fused to a drop of brownish glass. 
The non-refractory character of the diatomaceous earth is thus clearly 
demonstrated. It is also used in the manufacture of fire and heat- 
retarding cements and fire-proof building materials, such as solid brick 
and hollow brick for partition Avails and floors. 



MARYLAND GEOLOGICAL SURVEY 121 

Not all of the diatomaceous earth of the region is valuable, some con- 
taining an excessive amount of sand. At Lyons Creek wharf, in Calvert 
County, it is quite pure and has been worked for a number of years by 
the Maryland Silicate Company. Because of the limited demand for 
it and the considerable number of States in which diatomaceous earth 
is found it is improbable that the industry in southern Maryland will 
ever reach very large proportions. 

The Water Resources. 

The available water resources of St. Mary's County include the surface 
streams, natural springs, and the dug or driven wells. In the absence of 
large towns or great industries where large amounts of water are re- 
quired, the streams have not been utilized for water-supply purposes. 
In fact, it is doubtful if they could ever be depended upon for potable 
water because of the large amount of vegetation which they contain 
during the summer months and the liability to contamination from the 
run off of the adjoining cultivated lands. In some instances dams have 
been constructed and the power utilized by small manufacturing con- 
cerns, but because of the gentle slope of all except the smallest streams 
the amount of water-power developed is very slight. 

Springs. — The nature of the topography of the region with many 
stream-valleys cut almost to sea level combined with the gentle dip of the 
different beds of vai-ying permeability afford excellent conditions for the 
development of springs. The ground water sinking through the porous 
Pleistocene deposits until the less porous beds of the Miocene are en- 
countered, flows along the contact until it is tapped by some valley 
slope where it issues as a line of seepage or as a spring. A large per- 
centage of the ground water is not checked at the contact of the Pleisto- 
cene and Miocene but passes downward through the sandy layers of the 
latter formation until its further progress is checked by more argillaceous 
beds along which it flows until the layer outcrops at the surface. The 
more deep-seated springs of the latter sort which penetrate Miocene beds 
are apt to be purer than the shallow springs and furnish an unfailmg 
supply of excellent water. In addition to the increased danger of con- 
9 



122 THE ECONOMIC RESOURCES OF ST. MARY's COUNTY 

tamination in the shallower springs, they are very apt to fail in dry 
weather. 

Some of the springs are remarkable because of the large quantity of 
exceptionally pure water which issues from them, and also because of 
their continuous flow since the earliest settlement of the State with 
probably undiminished volume. The most famous one is Governor's 
Spring, a short distance east of St. ]\Iary's City, whicli w-as the first 
permanent settlement in Maryland and for a long time its capital. 
Another spring, equally well known, is the excellent spring at Charlotte 
Hall which has long furnished the supply of water for the boy's school 
at that place. 

While the spring-water is sometimes slightly charged wdth iron derived, 
in the main, from the Pleistocene deposits, it is, as a rule, remarkably 
free from mineral matter of any kind. Exceptions are the Diuretic 
Mineral Spring of Blakistone Island, from which water has been sold, 
and the chalybeate springs at Eock Springs, a few miles northwest of 
Blakistone Island. 

Dug Wells. — Except on the top of narrow divides between deep valleys, 
the ground "water level lies near the surface and abundance of water can 
be obtained from dug Avells of shallow depth. On the narrow divides, 
however, the water table in the dry months of the year lies only a little 
above sea level, thus necessitating -the sinking of wells almost to that 
plane in order to obtain a permanent supply of water. The highest 
divides in the county rise to an elevation of about 180 feet and in a few 
instances it has been necessary to sink wells to almost that depth to 
secure plenty of water during all seasons of the year. On the broad, 
low-lying flats bordering the Potomac IJiver, on the other hand, it is 
seldom that the wells exceed 20 feet in depth and sometimes tlu' water 
rises to the surface. In general the water in these most shallow wells 
is much more apt to be impure, although in many places it is used 
exclusively without any apparent injurious effects. 

Artesian Wells. — As good water in sufficient quantity can be ob- 
tained almost everywhere in the county at moderate depths few attempts 
have been made to obtain artesian w^ater, except in the low-lying regions 



MARYLAND GEOLOGICAL SURVEY 123 

adjoining the Potomac and Patuxent rivers, where flowing wells can 
be secured at moderate expense. Also in those localities the water in 
the shallow wells is sometimes brackish and at times become stagnant 
and unfit for drinking purposes. Few flowing wells are known within 
the county with sufficient artesian pressure to force the water more 
than a few feet above tide. The well at Chaptico, which rises 22 feet 
above tide, is exceptional. The water obtained in the artesian wells 
usually contains some mineral matter in solution but not sufficient to 
interfere with its use for most purposes. When the wells are protected 
from surface contamination, the artesian water is the most healthful 
water obtainable in the county. 

There seems to be three distinct water horizons that furnish the supply 
for artesian wells thus far sunk. One of these occurs in the deposits of 
the Aquia formation, one of the members of the Eocene, which probably 
underlies the entire county but nowhere appears at the surface in this 
region. To the northwest of St, Mary's Coimty, in Charles County, it 
rises to the surface and outcrops along many of the streams. The other 
horizons occur in the Miocene strata, one near the base of the Calvert 
formation and the other probably in the Choptank formation. 

The Eocene Jionzon. — This horizon supplies several artesian wells 
along the Potomac Eiver in the western part of the county. A well at 
Chaptico from which the water flows to a height of 22 feet above tide 
penetrates this horizon at a depth of 291 feet. Another well, 275 
feet deep, 2 miles west of Maddox, obtains its water from the Eocene, 
perhaps from strata somewhat higher than the water-bearing beds in 
the Chaptico well. Other wells supplied with water from the Eocene 
horizon include several wells at Oakley about 305 feet in depth, and 
one at Bushwood 287 feet deep. This horizon undoubtedly extends to 
the eastward, but since east of Oakley artesian water is obtainable from 
Miocene strata at shallower depths borings have not been extended to the 
Eocene horizon. 

The Miocene horizons. — The principal water-bearing horizon for the 
greater part of the county lies near the base of the Calvert formation. 
Many wells have been sunk to this horizon and a good supply of water 



124 THE ECOXOMIC KESOLKCES OF «T. MAKV's COUNTY 

has ahiiost invariably been obtained. On tlie raliixeni ]\iver side of 
tlie county irood flows of water are oljtaincd from a 'i'lo-io^^t well near 
Sotterly wharf, from two wells 290 feet iu depth at ^lillstone, and from 
two wells 257' and 287 feet deep east of Pearson post office. In some 
cases the wells have been sunk beneath the water-bearing horizon, thus 
making the horizon, from the depths of the w^ells, appear to be very 
uneven. In reality it seems to dip at a (juite uniform rate to the south- 
east, and consequently the wells in the lower portion of the county are 
deeper than those higher up the rivers. 

Along the Potomac River the Calvert liorizon furnishes the water for 
the 190- and -^Oo-foot wells at Lconardtown, a 270-foot well at Piney 
Point, numerous wells about 270 feet in depth on 8t. George's Island, 
several wells near St. Inigoes from 300 to 365 feet deep, a well on the 
west bank of Smith Creek 365 feet in depth, and two wells near Corn- 
laeld Harbor 360 and 370 feet deep. 

One other water-bearing horizon has been found at Cornfield Harbor 
at the depth of 240 feet. This is probably within the Clioptank forma- 
tion. It is probably less extensive than the l)asal Calvert horizon, since 
it has not been noticed elsewhere. 

The two principal water horizons described above have been penetrated 
by wells on the opposite side of the Patuxent Eiver in Calvert County, 
and on the south side of the Potomac Eiver in A'irainia. 



THE SOILS OF ST. MARY'S COUNTY 

BY 

JAY A. BONSTEEL 

Introductory, 

St. Mary's County comprises about 369 square miles of territory, 
bounded on the northeast by the Patuxent River, on the east by Chesa- 
peake Bay, on the south and southwest by the Potomac Eiver, and on 
the west by Wicomico Pdver and Budds Creek. All of these waters 
except Budds Creek are either salt or brackish, and in the Patuxent and 
Potomac rivers the tides rise to points far beyond the boundaries of 
the county. On the north, for a distance of about 25 miles, the boundary 
separating St. Mary's from Charles County is an irregular land line, 
except along the northeastern portion, where Indian Creek forms the 
boundary. 

The county is irregular in outline, constituting a large peninsula 
stretching southeastward and is the most southern of the Maryland 
counties occupying the western shore of Chesapeake Bay. 

St. Mary's County lies wholly within the Coastal Plain area of Mary- 
land. It consists of an. interior -upland division, rising from 90 to 200 
feet above sea level, and of a low-lying foreland border varying from 
15 to 45 feet above sea level. The county is very much indented by 
large estuaries or bays, particularly on the Potomac side. The streams 
of any length flow into the Potomac drainage system, while only steep- 
walled streams of short length are tributary to the Patuxent. 

As in Calvert County, the basal skeleton of St. Mary's County consists 
of unconsolidated strata. The materials composing these strata are the 
same as in Calvert County. In the same way the later Pleistocene de- 
posits are far more directly concerned in the formation of soil types 
than are the older strata, and the correlation of soil types with geological 



126 



THE SOILS OF ST. MARY S COUNTY 



formations given in considerable detail for Calvert County also applies 
to St. Mary's. 

The chief geological difference between the two counties lies in the 
fact that in St. Mary's the Eocene strata do not reach the surface, 
while in Calvert they do, and the St. Mary's formation is much more 
widely developed in southern St. Mary's tliau in Calvert. 



The Soil Types. 
The soils have approximately the following areas : 

Abeas of the Different Soils. 



Soils. 



Leonard town loam . . 

Meadow 

Norfolk sand 

Sassafi-as sandy loam. 
Sassafras loam 



Acres. 


Per ct. 


95,500 


41 


54,200 


23 


27,500 


12 


17,500 


7 


16,200 


7 



Soils. 



Norfolk loam 

Susquehanna gravel . 

Windsor sand 

Swamp 



Acres. Per ct 



8,500 
7,350 
3,450 
2,200 



The Norfolh Loam. 

Norfolk loam extends as a long narrow strip along the highest portion 
of the divide between the Patuxent Eiver drainage and that of the Poto- 
mac Eiver. It also occupies small, irregular, scattered areas covering 
the flat plateau of the northern portion of the county. 

Along the Three Notch Eoad, which follows the main divide of the 
county, the area occupied by the Norfolk loam presents a slightly rolling 
upland, varying from 120 to 165 feet in elevation. The highest eleva- 
tions and the intervening hollows are included in the area covered by 
this soil. 

The soil itself consists of a fine sandy to silty loam, reaching to an 
average depth of about 1 foot. When dry it is powdery and loose, re- 
sembling corn meal in texture, distinctly lacking the smooth, clayey 
feeling of the finer-grain Leonard town loam. When wet it packs to 
a firm surface, which cakes slightly through sun drying. In plowed 
fields this soil, though distinctly sandy, may clod into large-sized lumps. 
The subsoil is a reddisli yellow sandy loam, finer in texture than the 



MARYLAND GEOLOGICAL SURVEY 



127 



surface soil. It extends to a depth of about 30 inches and is almost 
universally underlaid by a coarse red sand mixed with fine gravel, having 
an indefinite depth. 

The soil supports a natural growth of pitch pine, white oak and black 
oak, and chestnut, this latter tree occurring more frequently on this 
soil than on any other type represented in the county. The areas of 
Norfolk loam occurring in the northern portion of St. Mary's County, 
particularly in the vicinity of St. Joseph's Church, constitute what is 





Mechanical Analyses of Norfolk 


Loam. 














t3 




la 
+^ 








a 


3 








as 


P 





10 





■-". 


a 










u 
5 


a 


-u 







"Sp 


lO 











^?n 





"^a 


^a 


°s 


sa 





-2 


No. 


Locality. 


Description. 




c 




c5 


® 

c3 

Q 




a) 


W3 

a-o 
> 


10 














P.et. 


Pet. 


Prt. 


P.r.t. 


P.ct. 


P.ct. 


P.ct. 


P.ct. 


6110 


234 miles W. of 
Sotterly. 


Yellow sandy 
loam, to 10 
inches. 


3.09 


2.64 


10.04 


12.43 


27.40 


12.45 


23.50 


9.70 


5112 


1 mile E. of New- 
market. 


Yellow sandy 
loam, to 14 
inches. 


1.61 


Tr. 


.53 


3.11 


36. 6T 


18.66 


31.08 


9.24 


5111 


Subsoil of 5110 


Medium red sand, 
10 to 40 inches. 


2.10 


3.61 


13.46 


14.35 


31.94 


7.78 


13.89 


14.91 


5113 


Subsoil of 5112 


Red sandy loam, 
14 to 30 inches. 


3.03 


0.00 


Tr. 


2.38 


35.11 


19.44 


17.32 


23.63 



locally recognized as one of the most desirable tobacco soils in the county. 
The average yield per acre is about 1300 pounds, and the average price 
about 6 cents per pound. Wheat, corn, and clover are also raised on 
this soil in regular rotation with the staple tobacco crop. The yield of 
these crops on the Norfolk loam compares favorably with the average 
yield of the same crops over the entire area of the county. 

The above analyses show the texture of the soil and subsoil of the 
Norfolk loam. 

The Leonardtoivn Loam. 
The most extensive soil type in St. Mary's County is the so-called 
white-oak or kettle-bottom soil of the upland. It extends from the 
vicinity of Eidge post office to the extreme northern limit of the county. 



1'2S THE SOILS OF ST. MAUY's COINTY 

The surface is slightly rolling or gently sloping, and the broad, flat divides 
between the minor streams are covered by this soil. As the soil bears 
quite a variety of local names, it has seemed best to supplant them all 
by the name Leonardtown loam. 

The extensive forests of white oak and pitch pine occurring over the 
upland region are found largely on this type of soil. Where small, 
irregular depressions without any outlet are found the sweet gum also 
flourishes. Where the Leonardtown loam is exposed on slopes to the 
\\n>hing action of rains, scalds or washes frequently form and they 
rapidly encroach upon the arable land. A permanent sod is the (tnly 
sure cure for these scars, though brush dams cause a temporary delay in 
the progress of erosion. 

Tlie cultivated areas of Leonardtown loam vary considerably in the 
amounts of the various crops produced. Wheat, corn, and grass are 
best suited to this soil, while tobacco is better adapted to lighter, sandier 
soils. This soil type forms the nearest approach to the heavy clays of 
limestone regions that is found in the Coastal IMain of ]\Iaryland. A 
treatment similar to that employed on the limestone soils should increase 
the productivity of the Leonardtown loam. 

The soil consists of a silty yellow^ loam, line and powdery when dry, 
but puddling to a plastic clay-like mass when thoroughly wet. On re- 
drying, this mass usually bakes to a hard, firm surface, or if stirred 
before being sufficiently dried, it clods up into hard lumps. The subsoil 
consists of a brittle mass of clay lenses, lumps, and fragments separated 
from each other by seams and pockets of medium to fine sand. The 
subsoil, if evenly mixed, would form a somewhat sandy loam, l)ut its 
peculiar structure causes it to act like a dense clay in its ])eliavior 
toward the water circulation. The lenses of clay are slightly flattened 
and their edges overlap somewhat like the shingles on a roof. Conse- 
quently, water in its passage through the subsoil, follows a roimdabout 
course along the sand-coated seams. Its progress downward is thus 
much delayed, and the subsoil is as impervious and as retentive of 
moisture as a heavy clay soil. The peculiar structure also gives rise to 
the brittleness noticed on plowing. 



MARYLAND GEOLOGICAL SURVEY 



129 



The bright-yellow color of the soil indicates a lack of organic matter. 
This can be corrected by plowing under green crops and by the applica- 
tion of stable manures. The tendency toward puddling and baking 
may be corrected by the application of lime. 

As has been indicated in the comparison of this soil with the residual 
soils of limestone areas, the Leonardtown loam is a type best adapted 
to the production of grass and grain crops, and certain portions of the 





Mechanical Analyses of 


Leonardtown Loam. 














-o 




10 





^ 







^ 












d 


-ij 


d 




a 











5 


a 





10 





•~i 


a 











tT 


a 




d 


•i^ 







d 








<D 




'"' 


■SS 


10 


ia 


8 





No. 


Locality. 


Description. 


^ 00 

92. 


'S 


3 

"3 




sa 

IS 


■§a 


too 


d 

s 




sa 

d 








C8 


> 
a 
h 


I' 
eS 



■a 


a 


3) 




4^ 



















S 


SI 


> 


m 











P.ct. 


P.ct. 


P.ct. 


P.ct. 


P.ct. 


P.ct. 


P.ct. 


p.ct. 


5114 


3 miles W. of Leon- 


Yellow silty loam, 


3.41 


Tr. 


.89 


1.33 


5.09 


11.37 


58.36 


19.90 




ardtown 


to 13 inches. 
Yellow silty loam, 


3.34 


0.00 


Tr. 


3.16 


17.63 


18.76 


47.75 




5116 


1 mile S. of Love- 


9.69 




vllle , ... 


to 13 inches. 


















5118 


43/4 miles E. of 
Leonardtown 


Yellow silty loam, 
to 10 inches. 


2.97 


Tr. 


1.38 


1.91 


3.87 


31.90 


58.46 


10.06 


5137 


3 miles yw. of 
Newmarket 


Yellow silty loam, 
to 9 inches. 


3.11 


Tr. 


3.05 


4.19 


9.79 


16.54 


55.70 


8.03 


5115 


Subsoil of 5114 


Yellow loam, 12 to 
34 inches. 


1.96 


Tr. 


.76 


1.19 


5.36 


13.93 


55.03 


31.94 


5117 


Subsoil of 5116 


Yellow loam, 12 to 
30 inches. 


3.07 


0.00 


Tr. 


3.38 


9.08 


11.96 


49.24 


33.59 


5119 


Subsoil of 5118.... 


Yellow loam, 10 to 
30 inches. 


3.44 


.67 


1.34 


1.83 


4.63 


15.46 


53.39 


30.37 


5138 


Subsoil of 5127 


Yellow loam, 9 to 
30 inches. 


1.56 


3.33 


4.78 


8.49 


15.97 


10.77 


36.42 


19.30 



area found in St. Mary's County are at present producing good hay and 
grain crops. The gradual introduction of live stock should largely 
increase the producing capacity of this soil, since the crops best suited 
to the soil can be fed directly to cattle. The saving in the fertilizer bill 
in this connection is an important item in farm economics. 

The above analyses show the texture of the Leonardtown loam soil and 
subsoil. 

The Susquehanna Gravel. 
The layer of gravel which almost uniformly underlies the upland 
soil types, particularly the Leonardtown loam, reaches the surface along 
all the more deeply cut stream valleys and along the slopes separating 



130 THE SOILS OF ST. MARY's COUNTY 

the upland from tlie low-lying foreland border. The gravel works down 
across the slopes wherever it reaches the surface, and forms long, narrow 
bands of a distinctly gravelly soil. While of no great importance either 
in area or in agricultural value, it forms a marked feature of the land 
surface. In some instances the component materials are coarse enough 
to form stony bands and patches along the slopes. In other cases the 
finer gravel accumulates sufficiently to form small areas of poor or 
almost useless soil. This is the case on some of the smaller hills of the 
northeastern part of the county, where broken fragments of iron crust 
mingle with the gravel and sands. 

Grapes are cultivated to advantage on similar soils in other regions, 
and their adaptability to this soil should be tried on a small scale in 
St. Mary's County. In general, it would be better to allow forest growths 
to occupy the larger, more intractable areas. 

The proportion of gravel in some of these areas is as high as 50 per 
cent, and with so coarse a texture it becomes almost impossible to main- 
tain a sufficient supply of moisture to mature any long-growing crop. 
This is especially the case where the gravel areas lie on steeply sloping 
surfaces. 

The ^Y^ndsor Sand. 

The "Windsor sand areas are found only in the northern portion of 
St. Mary's County. They are marked by a strong growth of pitch pine 
and by the gravelly and sandy texture of the soil. At present these 
areas are imperfectly tilled to tobacco and grain crops, or occupied by 
small land holdings devoted to producing garden crops for liousehold 
consumption. 

The soil consists of a coarse to medium sand, containing considerable 
gravel. It extends to about 10 inches in depth, and is underlaid by an 
even coarser sandy and gravelly subsoil, frequently containing iron crusts 
in sheets and in broken fragments. 

The value and capabilities of this soil have not been recognized as 
yet in this region. Its coarseness of texture, while precluding the profit- 
able cultivation of grain crops, adapts it especially to the culture of 



MARYLAND GEOLOGICAL SURVEY 



131 



early truck crops and peaches. The latter crop when raised on the 
Windsor sand produces a superior quality of fruit both in color and taste, 
and the orchards found on this soil in other localities are long lived, 
healthy, and profitable. 

The Windsor sand areas of St. Mary's County are all located within 
easy hauling distance of the present railroad points, and special crops 
of early fruits, vegetables, and peaches could find an easy and profitable 
market in the cities on connecting lines. 

The surface of the Windsor sand is generally level and is little sub- 





Mechanical Analyses of Windsor 


Sand 
















■a 
a 


a 

B 


o 

3 


o 
o 


o 

o 

°a 


o 
a S 


a 
a 

s 

o 
o 


o 
o 

.«a 


No. 


Locality. 


Description. 


tio 
o 

'S 

O 


o 


ia 

o 

OS 

o 

O 


rt (M 


as 

03 

a 


cc-o 

s 
> 


to 

o 
o 


o 








F.ct. 


Pet. 


P.ct. 


P.ct. 


p.ct. 


p.ct. 


p.ct. 


p.ct. 


6129 


Newmarket 


Coarse sand, to 


1.43 


5.48 


14.29 


14.04 


38.63 


15.16 


8.10 


2.(6 


5130 


SubsoHof 5129 


9 inches. 
Sand, gravel, and 
iron crust, 9 to 
28 inches. 


1.03 


10.20 


20.92 


12.18 


29.30 


11.58 


10.99 


3.81 



ject to washing on account of the porosity of the soil. It is easily 
cultivated and easily improved, and should form a valuable type for 
the special crops already discussed. 

The above analyses show the texture of typical samples of the soil and 
subsoil. 

The Norfolk Sand. 
The Norfolk sand illustrates the fact that a single soil type may arise 
from materials deposited at different geological periods. In St. Mary's 
County, soil of this type is found along the sloping sides of streams as 
an outcrop of some of the basal formations of the county; again it occurs 
along the lower courses of these streams as fiat-topped terraces built 
up from the older material by river transportation; while small areas 
of it occur along the forelands as material carried still farther seaward. 



132 



THE SOILS OF ST. :\rAHY S COUNTY 



All these deposits present the same sandy nature and Torin Hk^ same 
general type of soil, l)nt tliey vary greatly in geological age. 

Along tlie shallow stream channels of the forest area of the county 
narrow borders of this sandy soil are frequent. In the northern part 
of the county the streams have also cut into the sandy layer, which is 
the original source of this material. The covering of other materials 
has been washed away and considerable areas of Norfolk sand are ex- 
posed. Wherever found, this soil is recognized as well ada])ted to the 
^Maryland type of tobacco, and it shares with the Xorfolk loam in tlie 



Mechanical Analyses of Norfolk Sand. 



No. 



liOcality. 



Description. 



•a 




lO 


O 


. o 


^ 


lO 


B 
si 


s 


o 

o 


o 




o 


o 




o 

■M ■ 


-Hg 


p 


'= a 


oa 
Sa 


o 

■^a 


^2 

o 






a 


03-; 

too 


If 


SB 
o 


O 




£ 

O 
O 




o 
a 







sa 



5133 4 miles E. of Leon- Fine yellow sand, 

ardtown. to 14 inches. 

5135 I'U miles SW. of Medium yellow 

Hillville. sand, to 10 

inches. 

5134 ■ Suljsoil ot 5133 Medium red sand, 

j 14 to 36 inches. 

5136 Subsoil of 5i:j5 Ked sand and 

I gravel, 10 to 28 
inches. 



P.ct. 
1.44 


F.ct. 
Tr. 


F.ct. 

2.74 


P.ct. 
7.38 


F.ct. 
38.57 


F.ct. 
21.77 


1.36 


1.64 


8.74 


13.60 


34.69 18.76 


1.73 


Tr. 


3.31 


5.88 


34.91 


20.68 


2.00 


4.30 


12.65 


13.69 


31.22 


10.10 



F.ct. F.ct. 

22.37 4.82 

15.89 4.87 

23.53 11.96 

10.12 15.23 



reputation of producing a good grade and a reasonable quantity of the 
crop. 

The soil consists of a red or brown sandy loam, liaving a deptli of 
about 9 inches. This is underlaid by an orange or red sand to a depth 
of 3 feet or more. The natural growtli on this soil includes chestnut, 
oak, and laurel. The iSTorfolk sand is a tyi)ieal early truck soil, and 
has Ijeen very successfully farmcil in truck crops all along the Atlantic 
coast. It produces a quick grow th and early maturity, and is tlierefore 
much better adapted to the ti'ucking business than to the production 
of grain crops, which rcf|uirc a longer growing season. Peaches, pears, 
early potatoes, and the common garden vegetables should be raised much 



MARYLAND GEOLOGICAL SURVEY 



133 



more extensively than at jDresent upon this soil Avhenever transportation 
facilities permit of marketing. The wild fruits like the blackberry, 
which flourish so remarkably on this soil, should be replaced by the cul- 
tivated varieties of the same fruits. 

The table on the preceding page gives the results of analyses of this 
soil type. 

The Sassafras Loam. 
This soil type occurs in St. Mary's County at an elevation of from 60 
to 90 feet above tide in the form of flat-topped terraces. It is generally 



Mechanical Analyses of Sassafras Loam. 









-e 




o 


o 

.4^ 


d 


B 


a 


§ 








3 


a 
a 


o 


>o 


o 


■"J 


a 


R 












o 


lO 


o 

■o' _: 


o 


o 








4.) 


•— ■ 


^ 


"3 S 


C'l 


cS 


o 


2 . 








«^ 


o 




is 


°p 


^a 


d 

o 


^a 


No. 


Locality. 


Description. 


So 
o 

'3 


"3 


to " 








§ 

d 


d 








CS 


> 


u 


''-'. 


<s 


>» 




>^ 










6 


n 




a 




-4J 


3 








F.ct. 


P.ct. 


p.ct. 


p.ct. 


P.ct. 


P.ct. 


P.ct. 


P.ct. 


513" 


11*2 miles W. of 
Sotterly. 


Yellow siltj' loam, 
to 9 inches. 


2.22 


1.21 


4.51 


4.57 


14.94 


13.36 


49.87 


9.45 


5139 


1 mile S. of Great 

Mills. 


Yellow silty loam, 
to 9 inches. 


3.43 


1.02 


3.13 


4.53 


13.. 35 


13.14 


49.68 


12.80 


5138 


Subsoil of 5137 


Yellow sandy loam, 
9 to 30 inches. 


1.87 


.84 


4.51 


5.79 


33.63 


10.54 


33.84 


19.61 


^140 


Subsoil of 5139. . 


Heavy yellow 
loam, 9 to 30 
inches. 


2.17 


Tr. 


2.45 


4.03 


13.73 


13.63 


50.. 56 


14.16 



completely cleared and well cultivated. It forms the best corn producing 
soils of this and other areas and is well fitted for general farming pur- 
poses. It is formed from a mixture of sand and clay derived from 
much older strata and reworked and redeposited by stream action. 

The soil consists of a slightly sandy yellow or brown loam, having 
a depth of from 8 to 13 inches. This is underlaid by a heavier yellow 
loam to a depth of nearly 3 feet. This subsoil forms a good storage 
reservoir to maintain a moisture supply during the growing season 
without retaining enough water to interfere with cultivation or plant 
growth. Wheat, corn, and the grasses do well on this soil, while a fair 
tobacco crop can be raised on it; but it approaches more nearly to an 



13-i THE SOILS OF ST. MARY'S COUNTY 

easily -worked medium grade of soil for general farming purposes. 
Pears and other fruits, together with tomatoes, asparagus, and canning 
crops should be introduced to give a greater variety in crops with increased 
opportunities for profits. 

The use of lime and of green manures and stable manures will benefit 
this soil, though not so essential as in the case of heavier types. 

The table on Page 133 gives the analyses of Sassafras loam. 

The Sassafras Sandy Loam. 

Sassafras sandy loam occupies the low-lying forelands along the Pa- 
tuxent and Potomac rivers and along the shores of the numerous estuaries 
and creeks tributary to those rivers. In fact, this soil formation extends 
as a discontinuous belt of choice farm land almost entirely encircling 
the county. 

Lying between the more elevated uplands and the tide-water courses 
of the chief rivers of the section, the Sassafras sandy loam slopes gen- 
tly down from an elevation of about 35 feet nearly to water level, and 
presents a very nearly flat, though gently inclined, surface. Areas located 
on adjacent forelands are usually separated from each other by lower- 
lying strips of meadow lands located along the margins of the minor 
streams. To the rear of each area the surface usually rises with quite 
a steep slope to the more elevated plateau region. 

The soil itself is probably a marine deposit, laid down at a time when 
the relative level of tide water in this region was at least 40 feet higher 
than at present, though the plateau portion of the county existed as 
dry land even then. The deposition of material derived from the upland 
by the streams of that day took place closely adjacent to the land area 
which existed there, and the coarser sands were deposited in those stream 
courses as noted elsewhere. The finer sand and silt, carried to a greater 
distance seaward because of the lightness of individual grains, were 
deposited in the region of tide water, with the coarser materials falling 
in shallower water near shore, as is the case with the present deposition 
in all regions. Thus, small sandbars and spits would be formed, and 



MARYLAND GEOLOGICAL SURVEY 135 

organic matter from the mainland and from the tidal flats nsual along 
low shore lines would be commingled with the sand and silt of the 
bottoms of the estuaries. In such a manner the sandy loams of this 
foreland portion of the county most probably originated. As the rela- 
tive elevation of land and sea changed, this new-formed soil became 
exposed, and encroaching land vegetation further aided in the preparation 
of the loam for agricultural purposes. 

The soil is a dark-brown sandy loam, having an average depth of 
about 14 inches. The subsoil is heavier, in most instances consisting 
of a yellow or reddish-yellow sandy loam. At 30 inches depth the sub- 
soil is normally succeeded by a reddish sand, though frequently this is 
wanting and a silty drab layer is found, which extends nearly or quite 
to tide level. 

This soil is so well recognized as a desirable farming land that all 
original tree growth has been removed and the area is occupied by 
cultivated fields. Corn, wheat, and tobacco are raised on the Sassafras 
sandy loam, and the yield of each is somewhat higher than the average 
yield for the county. The average wheat crop will consist of about 15 
bushels per acre; that of corn about 7 barrels, or 35 bushels; while the 
tobacco will grow to 1600 pounds per acre, and will sell at 5 or 6 cents 
per pound. Of course, much larger crops are raised under favorable 
conditions, while unfavorable conditions of season or culture will corre- 
spondingly cause a decrease in yield. 

In the Cedar Point area the production of green peas, tomatoes, and 
of sweet corn for canning purposes has been undertaken. The climatic 
and soil conditions are favorable to profitable production of these and 
other crops classed as truck or canning crops. Along the Patuxent 
River, near Forrest Wharf, the culture of broom corn is being under- 
taken. The success of this attempt has not been learned. 

Owing to the location of this soil along the shore near shipping points, 
as well as to its texture and general properties, it is well adapted to the 
raising of fruits, vegetables, and general truck crops which derive value 
from being placed on an early market. Its position also makes irriga- 



136 



THE SOILS OF ST. .AIAHY S COUNTY 



tion possible whenever the Deeessity for intensified cultivation shall 
manifest itself in this community. 

The general character of the Sassafras sandy loam is indicated hy 
the following mechanical analyses. It is noticeable that the suhsoil in 
each case contains quite a laige percentage more of clay than does the 
corresponding soil. 



Mechanical Analyses of Sassafras Sandy Loam. 









■o 




10 





„ 





„ 








a 







+i 





4^ 


a s 








cs 


g 





us 





^ 


a ^ 








C 


B 









+i 





.s ° 


No. 


Locality. 


Description. 




QO 


c'a 
.1° 


?a 


ga 

330 


0.05 to 0.00 

, 0.005 to 
mm. 








IS 


2 


u 



-3 




>> 

u 

e 


ilt,i 
lay, 











a 





S 


s 


> 


30 1 a 








P.ct. 


p.ct. 


p.ct. 


P.ct. 


p.ct. 


P.ct. 


P.ct. \ P.ct. 


6141 


1% miles SE. of 
Stone Wharf. 


Brown sandy loam. 
to Ifi inches. 


2.55 


Tr. 


1.56 


4.30 


34.34 


11.86 


36.62 


8.36 


5144 


2^ miles S. of 
Leonard town. 


Brown sandy loam, 
I0 9 inches. 


2.22 


1.72 


10.83 


18.96 


19.85 


6.44 


31.94 


8.56 


5147 


P4 miles NE. of 


Brown sandy loam, 


3.50 


3.49 


12.30 9.40 


5.88 


10.16 


48.62 


6.24 




Trap. 


to 8 inches. 














5149 


34 mile NE.of Co- 
houck Point. 


Brown sandy loam, 
to 1:2 inches. 


2.93 


4.87 


17.49 11.83 1 11.08 


9.82 


30.59 


11.55 


5142 


Subsoil of 5141 


Heavy brown loam, 
Ifi to 154 inches. 


1.66 


.75 


2.67 


6.79 45.80 


5.87 


17.06 


19.30 


5145 


Subsoil of 5144 


Red loam, 9 to 30 


2.53 


1.58 


12.36 


18.69 15.99 


4.62 


30.43 


12.80 






inches. 


















6148 


Subsoil of 514" 


Yellow loam, 8 to 
.SO inches. 


2.T1 


.99 


7.03 


6.15 


3.76 


11.20 


51.80 


16.48 


6150 


Subsoil of 5149 


Yellow sandy loam, 
12 to 30 inches. 


2.15 


2.98 


13.72 


12.18 


9.74 


8.78 


26.13 


24.20 























The Meadow Land. 

The natural meadow lands of St. ]\[ary's County are usually flat or 
gently inclined areas occurring along stream courses or on the low, 
flat forelands bordering the tide-water areas. The meadows are usually 
rather wet, and in many instances they differ from adjoining soil types 
in their relation to drainage rather than in their texture. 

The natural forest growth over the meadows includes white oak, willow 
oak, sweetgum, and po])lar, with frequently a matted undergrowth of 
shrubs and vines. The meadows furnish a rather coarse, rank grass 
for grazing and, owing to the mild climate of the region, enttle frequently 
find pasturage throughout the winter. 



MAETLAND GEOLOGICAL SURVEY 



137 



The large meadow areas of the forelands are frequently cultivated to 
the general farm crops, but in wet seasons they are difficult of tillage, 
and even in the most favorable seasons they produce only wheat and 
grass to good advantage. They require extensive underdrainage ; even 
open ditches are inadequate, for the soil is so dense and so near water 
level that surface drainage fails to lower the level of standing water 
sufficiently to aerate the soil thoroughly. The presence of excessive 
water in the soil thus tends to keep the ground cold and to delay seed 
germination and plant growth. Then, too, the organic acids tend to 



Mechanical Analysis of Meadow. 









a 




lO 


2 




o 


a 


3 








c3 


n 


O 




o 




H 


^ 








4J 


a 
1—1 




o 




la 
ga 


8 


o 








"fl^ 


o 


^S 


eg H 


°a 




^a 


No. 


Locality. 


Description. 


'3 

bo 

o 


> 


5 a 

QQ 

i 




-sa 

00 

a 


u 

CD 
> 


o 
o 

m 


sa 








P.ct. 


P.ct. 


p.ct. 


P.ct. 


P.ct. 


P.ct. 


P.ct. 


p.ct. 


5151 


3 miles SE. of Bris- 
coe Wharf. 


Gray loam, to 8 
inches. 


1.84 


Tr. 


.88 


.83 


3.76 


33.35 


59.59 


9.58 


5 J 53 


One-eighth mile W. 
of Short Point. 


Brown silty loam, 
to 7 inches. 


2.33 


1.41 


3.83 


4.12 


6.46 


15.41 


58.54 


8.33 


5152 


Subsoil of 5151 


Drab clay. 8 to 30 

inches. 
Drab clay, 1 to 33 


2.89 


0.00 


Tr. 


1.V3 


5.38 


16.30 


47.55 


35.77 


515+ 


Subsoil of 5153 


1.61 


Tr. 


2.01 


3.61 


7.11 


11.40 


60.11 


14.74 






inches. 



















accumulate to excess, proving harmful to plant life and not fulfilling 
their function in the preparation of mineral matter to serve as plant 
food. 

Proper underdrainage by lowering the Avater level will not only drain 
off surplus moisture, but will also permit a circulation of air, and thus 
aid in the natural improvement of the soil. 

Many thousand acres of meadow land, now producing only a rank 
growth of grass or an uncertain crop of grain, can be made highly valu- 
able by relatively cheap methods of underdrainage. 

The soil of the meadow areas usually consists of 8 to 10 inches of 
gray silty loam underlaid by a subsoil of ash-gray clay loam. The soil 
mass is apt to be cohesive and clay-like when wet, hut when subjected 

10 



138 THE SOILS OF ST. MARY's COUNTY 

to the action of the frost and air it becomes powdery and crumbly, and 
is very rauoli improved in texture. Drainage and liming should be 
resorted to in order to produce this result on a large scale. 

The texture of this soil is shown by the analyses on Page 137. 

The Sivamp Land. 

There are three types of swamp lands in St. Mary's County — the tidal 
flats, which are wholly or partially submerged at each high tide; the 
fresh-water marshes, subject to frequent or constant inundation by 
streams; and the fresh-water bogs and swamps, due to incomplete head- 
water drainage or to natural or accidental artificial ponding of stream 
waters. 

The salt marsh at the head of Chaptico Bay and the flats at the head 
of Breton Bay are the most extensive examples of the first class occurring 
in St. Mary's County. Except at especially high spring tides these 
areas lie about 5 feet above the water level. They support a growth of 
marsh grass and reeds and possess a silty soil mixed with partially decayed 
vegetation. Some marsh hay is cut over these areas, and. cattle and 
hogs find pasture where the surface is sufficiently firm to support their 
weight. 

These marshy areas are formed by the deposition of fine sand, silt, 
and clay, brought down by streams and by the higher tides, together 
with the decaying remains of the vegetation which gains a foothold on 
the drier areas. These marshes are constantly growing in extent, and 
in many instances cattle are feeding on marshy meadows where small- 
sized boats floated in the early days of the colonization of the county. 
Farther from the mouths of the larger tributary streams, above the 
highest reach of the tide, the fresh-water marshes occur, as is the case 
along the Chaptico Creek, Mcintosh Eun, and many of the streams 
flowing into the Patuxent Eiver. These marshes are similar to the 
salt marshes, except that they are only subject to irregularly occurring 
inundations below fresh water instead of periodic submersion by the 
tides. 

The third class of swamps occupy positions at the heads of some of 



MARYLAND GEOLOGICAL SURVEY 139 

the main streams and along the upper courses of the majority of the 
smaller ones. The headwaters of the St. Mary's Eiver drainage, found 
in the forest area around St. Andrew's Church, illustrate this condition 
markedly, though many other localities are very similar. 

The surface in this forest area is slightly irregular and consists of 
Leonardtown loam and Norfolk sand. The hollows in both of these 
formations are swampy and grown up to gum trees. In wet seasons 
small ponds exist, which become dry, or nearly so, during the latter part 
of each summer. A slight clearing out of the natural drainage ways, 
connecting these ponds with stream courses, would destroy the ponds 
in most cases. Frequently the obstruction to drainage consists of a 
rank growth of vegetation, fallen tree trunks, and the accumulation 
of dead leaves and soil wash. In some few cases the grading up of 
highways or embankments constructed for proposed railways through 
the coimty has caused accidental artificial ponding of waters. These 
are of small extent and may be easily remedied by underdrainage. 

The Agricultural Conditions. 

The condition of agriculture in any community depends upon four 
factors — soil, climate, transportation facilities, and the mental and 
physical energy of the population. The first two of these factors are 
natural, while the last two are to a great degree artificial. Usually 
it does not lie within the power of any community, however energetic, to 
modify the soils or the climate of a region to any marked extent. The 
great exception to this statement is in the arid states, where irrigation 
has been introduced, transforming desert areas into fertile farms. 

The actual conditions of the soil, the climate, and the transportation 
facilities of St. Mary's County have been treated separately in other 
chapters, but a general resume of the interrelationships of these factors 
and a slight reference to certain social and economic conditions prevailing 
in the county are necessary to a full appreciation of the present status 
of the county by its own inhabitants as well as by strangers. 

The usual farm practice in St. Mary's County is based on a rotation 
of crops, including tobacco, corn, wheat, and grass, or a season of fallow- 



140 Tin: SOILS of st. mart's county 

ing. This rotation is observed on all soils in all parts of the county, 
though some individual farmers have modified it. Thus, in a great 
majority of cases, the fundamental factor of soil differences is neglected. 
The success of the rotation in the county has depended upon the highly 
accidental factors of the location of the farm and the energy of the 
farmer. Thus, the energetic man located on the proper soil for the 
tobacco crop will be highly successful, while his no less energetic neighbor 
located on the wrong soil may be unsuccessful, and the unenergetic man 
may absolutely fail. 

The natural selection of farm lands dependent upon tliose conditions 
has led to the abandonment of large areas of the Leonardtown loam to 
forest occupation, for the soil is not adapted to the culture of the 
quality of tobacco wliich buyers expect from the county. On the other 
hand, the jSTorfolk loam is tilled over almost every acre of its extent, 
because it is adapted to the production of this chief crop. 

In the same way natural selection has led to the extensive cultivation 
of the Sassafras sandy loam, and it is worthy of notice that the very first 
white settlers, as well as their Indian predecessors, located on this soil 
type chiefly because of its location near water transportation, but also 
probably in part because it is an excellent soil for general farming pur- 
poses. Contrasted with this soil are the large areas of meadow land 
still clothed with forest growth, though similarly located to the Sassafras 
sandy loam. It is not entirely an accident that leads to these selections 
and to the introduction of new crops, such as peaches, on the Norfolk 
sand, or to the cultivation of canning crops and broom corn on Sassafras 
sandy loam. The climate of the region is suited to the crops, the soils 
are similar to those upon which the crops have been raised elsewhere, 
the facilities for transportation are in part equal to the necessities of the 
crops, while the energy required for their introduction is supplied by 
well-informed and progressive citizens of the county and of other regions. 

A local and partly defined soil classification has been reached through 
this process of selection, though the areas suited to certain crops have 
not been located nor mapped over any part of the county until the 
present time. Nevertheless experience, often bought at a dear price, 



MARYLAND GEOLOGICAL SURVEY 141 

and confined to the few who have ventured their money and their time, 
has led to the partial classification already noted. It is hoped that the 
classification, the map, and the description of soil types contained in 
this report will facilitate further development along the lines of soil 
selection for special crops, will encourage the introduction of new crops, 
and will lead to a generalization of the experience gained hy the few 
for the use of the many. 

Closely associated with the adaptability of certain soil types to certain 
crops is the two-edged question of fertilizer, which is dependent for 
its answer upon the quality of soil to be fertilized and the kind of crop 
to be raised. 

Probably every soil type in St. Mary's County contains within 4 feet 
of its surface sufficient plant food to produce 100 crops of any kind 
which are raised or could be raised in the county. The necessity for 
fertilizer depends on the fact that much of this material is present in 
such chemical combinations and in such a physical state that some 
manipulation is required to release it and to bring it into solution in 
water so that the plant roots may absorb it. Certain chemicals found 
in commercial fertilizers and in stable manures tend to release this 
plant food and to form or supply soluble chemical compounds suited 
to the needs of the plants, while organic matter constitutes the best sponge 
for retaining the absolutely essential water supply in sandy soils, and 
acts equally well in loosening the too closely packed particles of heavier 
clay soils. The organic matter, through its decay, also furnishes actual 
plant foods and solvents for the preparation of other foods. The 
character of growth desired in special crops modifies the kind and amount 
of special fertilizers for those crops. For example, it is a generally 
accepted principle of tobacco culture in Maryland that liming land spoils 
the texture of the tobacco raised, causing it to spot and injuring the 
burning qualities for which it is so well known ; therefore the use of lime 
on tobacco lands is precluded, though its use would be of undoubted 
advantage on all of the heavier soil types and upon most of the lighter 
types for other crops. 

St. Mary's County possesses large stores of carbonate of lime in the 



1-12 THE SOILS OF ST. MAHY's COIXTY 

]\Iioe(.'ne marl l)cds iimlcrlying all of the upland portion of the count)'' 
and reaching the surface in nearly every cliif and stream cutting over 
the upper half of the region. This lime supply consists of the calcareous 
tests of marine shellfish which once lived upon the sea l)ottom when 
the ocean covered the county. The shells, huried in sand and elevated 
above water level, can be dug out by the ^^'agonload and converted into 
excellent lime by sieving out the sand and burning the remaining shells, 
just as lime rock is burned to lime. The sifting would be unnecessary 
in the case of some of the deposits, since the small amount of sand present 
would be a benefit to the heavier types of land. The Leonardtown loam 
would benefit materially from such liining, except, of course, when tolmcco 
is to be raised. 

Tlie plowing under of green crops, especially the leguminous plants 
of the clover and cowpea varieties, furnishes another method of enrich- 
ment highly desirable on almost all the soil types of St. Mary's County, 
and does not present the diiTiculties of liming, since this kind of fertilizer 
is of great benefit to the tobacco crop. These leguminous crops furnish 
a fair forage for cattle during a period of their gi'owth, and if allowed 
to continue growing they produce a mass of organic matter for incor- 
poration with the soil; and all the time, beneath the surface of the 
ground, certain minute bacteria, living on the roots, are taking nitrogen 
from the air and storing it in the soil, thus helping its enrichment. 

The ordinary practice of putting from 200 to 400 pounds of commercial 
fertilizer, costing from $18 to $40 per ton, upon the farms of St. Mary's 
County has a double effect. It produces the crop, but it also enters a 
large item on the expense side of the farm account, and on some soils 
its continued use has the efi^ect of burning out the soil, so that periods 
of fallowing become essential. For certain crops special fertilizers will 
always be necessary, and commercial fertilizers are to be commended 
highly, but in St. Mary's County on all soils the use of stable manure 
and the plowing under of green crops are to be preferred, while on 
the soils least suited to tobacco the al)an(lonnicnt of tluit crop and the 
free use of lime in conjunction with organic matter have already 
become necessary, as is shown by the forest areas given over to nature's 
cultivation. 



MARYLAND GEOLOGICAL SURVEY 143 

Many of the farm buildings of St. Mary's County are of remote date. 
The farmhouses particuhirly are types of colonial structure, and the 
residence upon the farm at Sotterly is one built for the first governor of 
Maryland, while numerous other manor houses in the county are nearly 
as venerable. Even the less pretentious houses display the long sloping 
roofs, the gable windows, and the large end chimneys of the early 
colonial period. The atmosphere of antiquity, of romance, and of his- 
toric interest which surrounds these old residences and the equally ven- 
erable churches and farm properties gives a local color and a local pride 
to the county that can be shared only by other communities of equal age. 

Outbuildings are not so essential in this climate as in regions of 
heavier snowfall, so the older farms are provided only with the tobacco 
barn, smokehouse, and corncrib of the plantation, the large stock and 
hay barns being almost totally unknown. Cattle can graze upon the 
meadow lands in all but exceptionally severe weather, and the side of 
some existing building or the shelter of woodland protects them during 
the coldest weather. 

The fences are mostly built of rails and poles cut in the native forests, 
though some barbed and other patent wire fences have been introduced. 
The Virginia rail or worm fence is the most common type, while the 
mortised post, into which the ends of the rails are fitted, is also common. 

Ko account of the condition of agriculture in St. Mary's County would 
be complete without a reference to the common draft vehicle and beast. 
Owing to the steepness of the grades and to the general difficulties attend- 
ing land transportation, the ox-cart is usually employed for heavy hauling. 
It is no uncommon thing toward the latter part of June to meet from 
one to twenty 4-ox or 6-ox teams attached to heavy 2-wheeled carts, 
upon which one or two tobacco hogsheads are being drawn to the wharves 
for shipment. Each hogshead constitutes an unwieldy mass of about 
800 pounds of tightly packed tobacco, and the successful transportation 
of some of these loads down the steep slopes from the upland to the 
wharf, under the existing road conditions, is no small feat of engineering. 

The field labor is largely performed by the numerous colored population 
of the county, some of whom labored as slaves on the same farms where 



144 THE SOILS OF ST. MARY'S COUNTY 

they now work as free men. The majority of the workers, however, be- 
long to a more recent generation. 

There are no large towns in St. Mary's County. Leonardtown, the 
count3'-seat, is the largest, while Mechanicsville, at the terminus of 
the railroad, does a thriving business, and Charlotte Hall is the seat of 
a well-known school of the same name. 

The tendency of the white population is to\\ard the enjoyment of the 
seclusion of large estates, and frequently the manor house or farmliouse 
is reached only by a long avenue leading away to a distance of nearly 
a mile from the public highway. On the other hand, the colored popu- 
lation segregates into little communities, where land may be obtained 
cheaply, and little villages of frame and log dwellings are dotted over the 
county. 

The Transportation Facilities. 

A single branch line of railway, connecting Mechanicsville with the 
main line at Brandywine, is the only rail communication between St. 
Mary's County and the markets and cities of the State and the country at 
large. This lack of railroad communication is partly relieved by the 
steamboat service on the Patuxent and Potomac rivers and on the larger 
streams. As two lines connecting with Baltimore and Washington control 
the water transportation, this can scarcely be said to equal the needs of 
the county. The boats run only at long intervals and at rather irregular 
times, and the trip to Baltimore or Washington consumes from sixteen 
to twenty-four hours, depending upon the volume of freight carried. 

For this reason the crops produced in the county are placed at a dis- 
advantage with relation to markets when compared with those of other 
regions, and the variety of crops that can be raised with profit is con- 
siderably restricted. This is particularly evident in the case of fruit 
and truck crops and of dairy products. The truck lands of St. Mary's 
County are excellent, so far as soil and climate are concerned, but no 
one cares to enter into their cultivation to any extent so long as the 
cost and uncertainties of marketing remain as great as at present. Again, 



MARYLAND GEOLOGICAL SURVEY 145 

the Leonardtown loam, the Sassafras loam, and the meadow lands are 
well adapted to_ dairying and to stock raising, but the time distance from 
markets and the actual uncertainty of any communication during win- 
ter months retard or prevent introduction of stock. 

The waterways for extensive steamboat communication exist, grades 
well adapted for railway construction are to be found, and the con- 
struction of the roadbed presents only the simple engineering problem 
of cut and fill, with no consolidated rock formations to require blasting. 
The soils, the climate, and the natural advantages of geographical loca- 
tion all favor the upbuilding of the county. It is likely that outside 
influences have combined with a well-defined conservatism in the native 
population to retard the development not only "of this but of other locali- 
ties in the general region. 

The internal communications of the county consist of highly varied 
wagon roads. The main roads follow the main divides, while public 
and private roadways lead out along the secondary divides and down 
to the lowland farms and to the wharves. Bridges are scarce, and the 
small streams are crossed by fords. The tide-water indentations along 
the coast and the marshes at their headward extremities separate the 
farms along the forelands, and it is possible to go only from one foreland 
to another by considerable detour inland, usually including a steep ascent 
to the upland and an equally steep descent to the adjoining foreland. 
Foot passengers can usually find a small boat to transfer them across 
such obstacles, and many of the farmers own sailboats, but regular 
ferries do not exist. There is no regular ferry or bridge across the 
Patuxent terminating in St. Mary's County. 

The wagonroads consist of sand, loam, or clay, as they happen to 
cross such materials, and the- rain wash and the wear of travel have 
cut the roads down for long distances far below the surface of the 
country. In many places where the roadway has been washed to a state 
of impassability teams have driven around the gully and established a 
new highway, or an overturned tree is avoided similarly. One road 
district in particular has secured fairly good roads partly through the 



146 THE SOILS OF ST. MARY's COUNTY 

energy of its supervisor, partly because additional contributions above 
the annual tax have been given b}^ residents of the district, and partly 
because the district contains better road materials than some others. 
The iron-stained gravels of the upland plateau should be used to a greater 
extent in surfacing its clay roads, but proper drainage and grading of 
most of the roads must precede any other work. 



THE CLIMATE OF ST. MARY'S COUNTY 



BY 

C. F. VON HERRMANN 



Introductoey. 
The extreme southern boundary of Maryland is located at the mouth 
of the Potomac River, near the Virginia shore, in latitude 37° 53' N. 
Point Lookout, at the southern extremity of St. Mary's, is only a few 
miles farther north, and the region whose climate is to be discussed m 
this chapter, thus forms one of the most southern counties of Maryland. 
As the county is distant from the mountains, its surface level, and its 
coast line deeply indented by rivers and tidal estuaries, it is apparent 
that the factors immediately controlling the character of its climate 
are its relatively low latitude (38° 2' to 38° 31' N.) and the proximity of 
large bodies of water. The mitigating influence of water on climate 
has been sufficiently discussed in the chapter on the climate of 
Calvert County to which the reader is referred. In that sketch it was 
shown that the waters of the Bay and Atlantic Ocean have much less 
influence than might be expected on account of the prevailing ofE-shore 
winds. It was also shown that as the cold Labrador current flows near 
the Atlantic coast the waters bathing the shores of Maryland and the 
interior waters of the Bay are below the temperature normal to the 
latitude. The popular belief that the Gulf Stream itself has an influence 
on the climate of Maryland is quite erroneous. The temperature of 
St. Mary's County will probably be found to be slightly higher than 
that of its northern neighbor, Calvert County, but its northwest portion, 
which is farthest removed from the Bay will have a large range of 
extremes. In the present study of the various meteorological elements 
the mquiry should be kept in mind to what extent does the climate of 



148 THE CLIMATE OF ST. MARY's COUNTY 

St. Mary's County differ from what may be designated the normal for 
its latitude. 

This region shares all the characteristics common to the coastal plain, 
the most important of which, from a climatic point of view are, its 
low, level surface, its unconsolidated soil of sand and clay, and its con- 
siderable area of forests. The peculiarities of the drainage in this 
region is remarkably well shown in St. Mary's County. The water-shed 
lies very near the valley of the Patuxent Eiver the entire distance from 
Charlotte Hall to Jarboesville, and farther south it continues quite 
near the Chesapeake shore. Thus the rivers drain south and southwest 
into the Potomac, at right angles to the general direction of drainage 
in the Piedmont Plateau. The general elevation is somewhat over 100 
feet, approaching 200 feet in places. Isolated elevations of over 100 
feet are found even in the extreme southeast portion of the county, for 
instance near Friendship, which is a few miles from the shore, north of 
Point Lookout. The level areas of 100 feet elevation are more num- 
erous and broaden out toward the northwest portion of the county. All 
the meteorological stations, except Charlotte Hall (167 feet) have an 
elevation of less than 50 feet, that is they are situated on low ground at 
the head of small bays. 

Climatic Data Available. 
Although climatic records are available for seven stations in St. Mary's 
County, the periods of observations are all short and much broken. The 
earliest observations in the county were taken under the auspices of 
the Smithsonian Institution, by Mr. T. G. Staggs, at Ridge, from 1856 
to 1857. Other early records are those by Dr. Alexander McWilliams, 
at Leonardtown, from 1858 to 1859, and by Rev. James Stephenson, 
at St. Mary's City, from 1859 to 1870. At Cherryfields (P. 0. Valley 
Lee) observations were taken by Col. J. Edwin Coad for a period of 
five years, from 1893 to 1899. The rainfall records for St. Inigoes 
taken by Mr. James F. Ellicott, from 1871 to 1879, must be used with 
caution. For all of these stations only the mean temperatures and the 
monthly precipitation are available. The only fairly complete record 



MARYLAND GEOLOGICAL SURVEY 149 

for St. Mary's County is that for Charlotte Hall in the northwest portion 
of the county. Here Prof. J. Francis Coad took meteorological obser- 
vations from 1893 to 1904, but owing to frequent absence from station 
the records are unfortunately not continuous, varying in length from 
7 years for June to 11 years for January. Table XXIV, page 176, gives 
the necessary information in regard to each station in the county. St. 
Mary's City, St. Inigoes, Eidge, Cherryfields, and Porto Bello are located 
not "far apart in the southern portion of the county, near St. Mary's 
River; Leonardtown is at the head of Breton Bay; and the most northern 
station, Charlotte Hall, lies near the boundary of Charles County. 

From the fact that records of temperature extending over many years, 
such as the period of 200 years at Florence, 100 years at Paris and 88 
years at Baltimore, show no change from the annual course of tem- 
perature at present observed, in spite of the great variation in the 
monthly means, it is concluded that every place has a normal march 
of temperature which can be ascertained only by a series of observations 
of considerable duration. The length of the period required to obtain 
a correct normal depends largely upon the character of the climate. In 
tropical regions where the seasonal variations are small, five years are 
sufficient to give an annual mean temperature accurate to within 0.1°, 
but such is by no means the case in a variable, continental climate like 
that of the eastern United States. At Baltimore the probable error of 
the means for 88 years is still greater than 0.1°. Means for less than 
20 years at any station in Maryland are far from representing true 
normal temperatures. At Baltimore the January mean temperature has 
varied from 43.9° in 1858 to 21.3° in 1893, a difference of 19.6°; at 
Solomons the variation in the February means was from 40.8° to 26.2°, 
a difference of 14.6° in 14 years. Therefore, in comparing short term 
records at several stations it is impossible to determine whether the 
differences observed are really due to actual differences in climate, or 
are due to the special character of the short period from which the 
means were derived. This is well shown by comparing the excellent 
record for 14 years at Solomons (1892 to 1905) with the 88 year means 
at Baltimore, when it appears that Solomons is colder than Baltimore 



loO 



THE CLIMATE OF ST. MARY S COUNTY 



in January and Febniarv, an entirely ei'i'onoons eoneliisidii : I'oi- by 
comparing the Baltimore and Solomons records for the same period 
of years, the proper relation of toin]~)oratnrc for the two stations 1)ecomcs 
at once apparent.' 

Mcaiv temperatures for short periotis may, however, be corrected, when 
there is available for comparison a long record at a station not far 
distant, and similarly located with respect to its topographic surround- 
ings. For Lamont has shown that in spite of the variability of the 
temperatures from month to month, the differences between neighboring 
places remain constant. These differences are fixed by physical causes 
and so may be strictly considered a meteorological constant (Ilann). 
Baltimore is not very differently situated from other stations in southern 
Maryland, and its record for 88 years may be used as the criterion by 
which to ascertain the corrections to be applied to short term records 
to obtain the true normals. The application of the method may be 
conveniently illustrated by an example. 

The January mean temperature at Baltimore (88 years) is 34.9°; the 
January mean for Charlotte Hall (10 years) is 34.0°. Charlotte Hall 
is 56 miles south of Baltimore, and cannot normally have a lower mean 
winter temperature than Baltimore. The correction to be applied is 
calculated as follows : 



Charlotte HaU. 

Departures . 

Baltimore 

DiH'ereuce-... 

Departures . 



1894 


1895 


1896 


1897 


1898 


1899 


1900 


1901 


1902 


1904 


38.6 


33.8 


33.6 


33.2 


38.3 


34.3 


36.3 


34.4 


31.6 


29.8 


4.6 


-1.3 


-0.4 


-0.8 


4.3 


0.2 


2.3 


0.4 


-2.4 


-4.2 


37.4 


31.4 


,33.3 


30.8 


36.7 


32.7 


35.3 


34.4 


31.5 


27.4 


1.2 


1.4 


0.3 


2.4 


1.6 


1.5 


1.0 


0.0 


0.1 


2.4 


0.0 


0.2 


-0.9 


1.2 


0.4 


0.3 


-0.2 


0.0 


-1.1 


1.3 



34.0° 
2.O0 

32^8° 
2_oo 

0.19 



2 Dlfiferenco between Charlotte Hall and Baltimore. This first column of departures 
is the departure from the average of the mean temperatures ; the last column of 
departures is the departure from the normal of the dilleronees between Baltimore and 
Charlotte Hall. , 

The average of the variations of actual mean temperatures at Charlotte 
Hall is 2.2°, with a probable error for the 10-ycar period of plus or 
minus 0.6°: but the average of the variations in the differences between 



' See the chapter on climate in Calvert County Report. 



MARYLAND GEOLOGICAL SURVEY 151 

the Baltimore and Charlotte Hall means is only 0.1°, or twenty times 
less, and the probable error is only phis or minus 0.03°. As the mean 
for January at Baltimore for 88 years is 34.9°, and Charlotte Hall is 
normally 1.3° warmer (probable error 0.03°) the corrected January 
mean for Charlotte Hall is 34.9° plus 1.2°, which is equal to 36.1°. The 
corrected mean temperatures given in Table I have all been ascertained 
in this way. 

In order to secure a fairly accurate mean temperature for St. Mary's 
County, the corrected means for the following stations have been em- 
ployed, viz.: Charlotte Hall (9 years' record) situated in the northwest 
portion of the county, Cherryfields (5 years), St. Mary's (7 years), and 
St. Inigoes (7 years) in the southern portion of the county, and 
Solomons (14 years) near the middle of the northern shore. 

The Temperature Conditions. 

The average monthly and annual mean temperatures corrected as 
indicated are given in the second part of Table I. The upper portion 
of the table contains the original uncorrected data for all stations in 
the county. The annual mean temperature for St. Mary's County is 
foimd to be 57.1°. This is slightly higher (0.3°) than the mean for 
Calvert County. Spring (55°) and autumn (59°) have the same tem- 
perature as Calvert County, but summer (76°) is about a degree cooler, 
and winter (38°) a degree warmer, a difference which may be attributed 
to the superior influence of the Bay. The warmest month is July, with 
a mean of 78°, and the coldest January, with 37°, giving an annual 
range of 41°. The extremes in St. Mary's County are, maximum 104° 
at Eidge in Jnly, 1856, and minimum 19° below zero at Charlotte Hall 
in February, 1899." The range in absolute temperatures is 123°. 
Maximum temperatures of 100° or above have also been recorded at 
Charlotte Hall and St. Inigoes, and 2° below zero occurred at Leonard- 
town during the cold winter of 1893. 

The monthly mean temperatures at all stations are given in Tables II, 
III, IV, V, VI, VII, and XV. 

- See the remarks in regard to this record on page 168. 



152 



THE CLIMATE OF ST. MARY S COUNTY 



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MARYLAND GEOLOGICAL SURVEY 



153 



TABLE IL 
Monthly and Annual Mean Temperatukes i at Cherrtfields, Md., 1893-1899. 



Year. 


d 


.Q 


.a 


P. 







3 


iii) 

3 


ft 


o 


> 
o 


d 


as 
3 

a 
a 




1-5 


fa 


S 


< 


S 


■-5 


•-5 


< 


m 


O 


^ 


w 


< 


jg93 






1 












69.3 46.9 
59.0 44.8 


39.5 
38.3 




1894 


39.4 


37.4 


48.2 


5L8 


66.0 


73.8 


76.6 


73.6 


73.6 


56.6 


1895 


33.3 ' 25.9 


4L8 


53.9 


63.8 


74.3 


73.3 


76.0 


73.3 


53.4 46.9 


38.3 


.54.3 


1896 


33.8 , 36.8 


39.0 


55.4 


67.8 


7L7 


76.4 


76.3 


67.8 


55.4 5L3 


35.7 


55.5 


1897 


3L8 1 36.4 


45.3 


53.9 


61.5 


70.5 


76.8 


74.8 


ti9.4 


59.9 


47.3 


39.4 


55.4 


1898 


37.6 


34.4 


47.6 


50.2 


63.6 


73.4 


77.5 


77.4 


73.2 


60.6 


45.9 


37.0 


56.3 


1899 


34.8 




















































Means 


34.9 


34.3 


44.4 


53.6 


64.2 


73.3 


76.1 


75.3 


70.8 


57.9 


47.3 


38.0 


55.7 



1 Observations at 8 a. m. and S p. m. 



TABLE III. 
Monthly Mean Temperatures at Ridge, Md. 































Year. 




.Q 


2 


Vh 


>> 


3 


tA 


isi) 


•s 




> 


6 


3 




^ 


O 


03 






3 


3 


3 




o 


o 


ID 


C 




>-> 


fa 


s 


< 


^ 


<-> 


*1 


< 


02 


O 


15 


q 


< 


1856 










67.8 


79.1 


84.1 




73.1 


59.3 


48.6 


34.6 




1857 


36.6 


43.3 


41.8 


49.6 


63.3 


78.4 

































Table I and subsequent tables contain the monthly and annual mean tem- 
perature and total precipitation at all stations in St. Mary's County. 
Table XXIV gives the necessary statistical data. The following remarks 
are pertinent: 

The observations at Charlotte Hall were commenced by Mr. R. W. Sil- 
vester in 1892, but were continued by him for less than a year, therefore, the 
larger portion of the work at the station is credited to Prof. J. F. Coad. 
In 1905 Rev. J. Neilson Barry became observer at Charlotte Hall, and it is 
hoped a new and valuable series of records will be secured for that station. 

At Cherryfields the temperatures were observed at 8 a. m. and 8 p. m.; 
the means given in Table I, are the original records, but the corrected means 
were reduced to the equivalent of maximum and minimum readings by 
applying a correction determined by the difference between the means from 
8 a. m. and 8 p. m., and from maximum and minimum temperatures at Balti- 
more. At Leonardtown the means are from observations at 7 a. m. and 2 
and 9 p. m. These have not been corrected to the means of maximum and 
minimum temperatures because the differences are very small. 

As regards precipitation the records at St. Inigoes are of doubtful value; 
at Charlotte Hall the irregularity of the record causes the rainfall to come 
out too small for the period. 

11 



154 



THE CLIMATE OF ST. MARY S COUNTY 



TABLE IV. 
Monthly Mkax Temperatuuks at Porto Bei.lo, Md. 



































Year. 


a 


.d 


J3 

o 

03 




& 


a 


3 


3 




+3 


o 




03 

a 
c 






1-5 


f^ 


s 


«; 


S 


1-5 


►-5 


«<5 


CO 


O 


12; 





<5 


1RQR 


31.3 


38.3 


46.5 


5i.O 


66.8 


73.8 


79.0 


76.3 


70.4 

















TABLE V. 
Monthly Mean Tempekatures at Leonardtown, Md. 



Year. 


a 

1-5 




p 
3 


a 
< 


si 


6 
3 

1-5 


P 


60 

p 
< 


p. 


4J 
O 


> 


6 

* 


C3 

C 
B 


1858 

1859 

1889 


42.9 
37.3 


















40.4 
48.1 
47.3 


41.1 
33.8 
45.8 




38.2 


49.9 


52.1 


64.2 


72.1 


75.4 


74.4 


69.6 


51.7 


55.6 


1890 

1891 


^^ o A.i o 


41.8 


53.0 
54.3 
51.7 
52.6 


ei.b 

60.0 
62^8 














'^ 


71.3 
'12.8 


70.2 
78.0 

78.2 


"76!6 


71.2 
66.2 


'59'.2' 


41.9 
46.8 


34.6 




1893 




37.1 


3". 4 
42.5 




1893 


25.6 


36.3 


















Means 


37.5 


39.0 


42.9 


52.7 


63.0 


72.0 


75.4 


75.5 


69.0 


56.4 


44.9 


38.8 


55.4 



TABLE VI. 
Monthly and Annual Mean Temperatures ' at St. Mary's, Md., 1850-1S70. 



Year. 



1859. 
1861. 

1863. 
1863. 
1864. 
1H65. 
1866. 
1867. 
18R8. 
1869. 
1870. 



35.6 
38.4 



38.0 
32.4 
3:^.1 
I 37.1 
30.9 



Means 35 



39.5 



43.1 



42.6 
38.8 
36.8 
36.8 
,37.0 
37.1 



44.4 
41.8 



40.4 
49.9 



3B.9 
35.3 



40.2 
43.0 
39.4 



54.1 
53. 9 
49.2 
53.9 
58.7 
57.0 
.56.0 
59.1 
53.2 



.9 42.7 56.0 



61.1 
61.9 

kl.9 
64.5 
61.2 
60.8 
61.9 



61.9 



72.2 
7o!9 
73.0 
76.6 



74.7 
75.4 
76.9 
76.2 
76.1 



78.8 



79.7 
76.5 



71.9 

72.2 76.1 
77.6 



72.6 76.1 



78.0 



78.0 



70.5 
66.9 
68.9 
74.9 



71.3 
70.6 



70.5 



62.4 

61.8 
57.2 
56.8 
57.3 



48.3 
49.6 

48.3 
47.4 



40.8 
40.1 
40.0 
38.4 
40.8 
40.8 



56.1 
57.6 



59.8 
54.8 
52.6 



48.3 
41.6 



36.1 
a3.3 
40.0 



54.0 



57.8 ; 47.2 38.9 



66.1 



Highest Means. . ■ 
Lowest Means. . . . 
Range 



1 42.1 


42.6 


2r.l 


30 5 


15.0 


12.1 



49.9 ' 59.1 

39.4 49.2 

10.5 9.9 



64.5 

60.8 

3.7 



T6.6 


77.5 


79.7 


74.9 


62.4 


49.6 


40.8 


70.9 


74.7 


76.6 


66.9 


52.6 


41.6 


33.2 


5.7 


3.8 


4.3 


8.0 


9.8 


8.0 


7.6 



67.6 

56.1 

1.5 



^ Means from 7 a. m., 2 p. m., and 9 p. m. observations. 



MARYLAND GEOLOGICAL SURVEY 



155 



TABLE VII. 
Monthly and Annual Mean Temperatukes at St. Inigoes, Md. 



1871-1879. 



Year. 



1873 
1873. 
1874. 
1875. 
1876 
1877. 
1878. 
1879. 



Means 



33.1 
35.0 
44.5 
33.6 
46.3 
35.8 
41.0 
37.4 



34.7 
44.5 
43.5 
34.8 
43.0 
43.6 
40.0 
38.6 



36.7 
43.3 
45.3 
43.6 
39.4 
47.8 
53.9 



56.0 
53.4 
49.6 
51.4 
55.4 
54.6 
66.3 



66.0 
63.0 
65.3 
65.3 
66.0 
63.8 
65.3 



38.3 



40.1 



44.1 



55.3 64.9 



73.7 
73.5 
76.6 
74.4 
76.9 
74.9 
66.6 



73.8 



76.8 
80.0 
76.6 
79.5 
83.0 
79.8 
80.9 



73.9 
75.7 
77.4 
74.9 
78.1 
79.5 
73.3 



79.4 



76.1 



65.7 
67.4 
70.6 
73.9 
68.1 
69.6 
60.3 
73.5 



53.4 
58.9 
56.4 
59.1 
57.9 
64.6 
61.9 



46.4 
43.6 
47.8 
49.9 
47.7 
51.4 
63.9 
53.3 



35.8 
33.3 



43.3 
45.0 
34.6 

47.8 
38.7 



50.1 



39.5 



53.8 



58.3 
56.4 
.58.3 
59.5 
59.4 



57.4 



Highest means 
Lowest means. 
Range 



46.3 


44.5 


53.9 


66.3 


66.0 


76.9 


83.0 


79.5 


73.5 


64.6 


63.9 


+7.8 


32.1 


34.7 


36.7 


49.6 


63.0 


66.6 


,76.6 


73.3 


60.3 


.53.4 


43.6 


32.3 


14.3 


9.9 


17.3 


16.6 


3.0 


10.3 


5.4 


6.3 


13.3 


11.3 


30.3 


]5.6 1 



59.4 
53.8 
5.6 



The marked contrasts in the summer and winter mean temperatures 
in St. Mary's County are characteristic of a continental climate, and 
the differences become more striking if comparison be made between 
exceptionally warm summer months and nnnsually cold winters. The 
highest Slimmer and the lowest winter means for each station are given 
below : 

station. Highest Summer Mean. Lowest Winter Mean. 

Charlotte Hall 81.8° in August, 1900. 25.8° in February, 1895. 

Cherryfields 77.5° in July, 1898. 25.9° in February, 1895.i 

Leonardtown 78.2° in July, 1893. 25.6° in January, 1893. 

Ridge 84.1° in July, 1856. 26.6° in .Linuary, 1857. 

St. Inigoes 82.0° in July, 1876. 32.1° in January, 1872. 

St. Mary's 79.7° in August, 1864. 27.1° in January, 1867. 

1 From observations at 8 a. m. and 8 p. m. uncorrected. 

The highest monthly mean temperature in the county was 84.1° in 
Jul}', 1856, at Eidge, and the lowest was 25.6° in January, 1893, at 
Leonardtown, giving a large range of 58.5°. 



THERMAL ANOMALIES. 

We may now inquire Avhat relation does the corrected mean tempera- 
ture for St. Mary's County bear to the normal temperature for its latitude, 
in which the effect of the distribution of land and water peculiar to 
the region in question may be considered to be equalized, if not elimi- 



150 THE CLIMATE OF ST. MAUY's COUNTY 

nated? The well-kuown isothermal charts showing the distribution 
of temperature over the globe are constructed by entering on a chart of 
the world the mean temperature for each station reduced to sea-level, 
and drawing lines through points which have the same temperature. 
From these charts it is possible to calculate the mean temperature of 
each parallel of latitude. The mean temperature for equidistant points 
on each parallel is ascertained, for instance, at the crossing point of 
every 10 degrees of longitude, giving 36 values, the average of whicli 
is the normal temperature for the parallel. This normal may be viewed 
as the temperature which would result at the given parallel from an 
equable distribution of land and water, instead of the irregular dis- 
tribution found in nature. A comparison of the actual mean tempera- 
tures observed with the normal for the latitude will show whether a 
region is warmer or colder than the normal or the thermal anomaly of 
the region. 

The parallel of 38° N. is the nearest to St. Mary's County. The mean 
temperatures for this latitude, as found by Spitaler, and the corrGspond- 
ing means for St. Mary's County are given below : 

Annual Mean January July 

Temperature. Mean. Mean. 

Parallel of 38° N 59.5° 44.2" 76.5° 

St. Mary's County 57.1° 37.1° 77.8° 

Differences — 2.4° — 7.1° + 1.3° 

The comparison shows that the annual mean temperature of St. Mary's 
County is 2.4° lower than the temperature proper to its latitude. The 
thermal anomaly is negative throughout most of North America (except 
the Pacific and Gulf coasts) and the deficiency exceeds 7° in the region 
northwest of Hudson Bay. In winter St. Mary's County is 7.1° colder 
than the normal for its latitude, or in other words the character of the 
year is determined by the severe winter climate of the great continental 
interior. Nortli of the l^akcs and the St. Lawrence tlic thermal anomaly 
for January is — 18°, while it is -{- 30° between Iceland and Norway. 

In summer the anomaly for St. Mary's is positive, but only slightly 
over a degree, the difference between the July means being 1.3°. The 
positive anomaly becomes greatest towards the interior of the continent, 



MARYLAND GEOLOGICAL SURVEY 



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158 



riii: ci.iArATE of st. mary's county 



reaching -[-18° i" Arizona and Soutliern California. It is — 10° l)et\veen 
the coast of Labrador and Greenland. The line of no departure lies 
not far east of the Atlantic coast both in summer and in winter. 

Precipitation. 

Table VIII gives the monthly and annual precipitation for all stations 
in St. Mary's County. A critical examination of the material will lead 
to the conclusion that the annual average at St. Inigoes is above the 
true normal for the region; the total amount for the year 1872, which 
is 88.51 inches, is so much larger than the amount recorded anywhere 
else in the State that it should not l)c used. The period covered by 
this record (1871 to 1879) is too short to establish a normal record, 
moreover it is known to have been one with excessive rainfall, especially 
the years 1873, 1876, and 1879. The precipitation at Charlotte Hall 
appears too low, though it is known that there has been a rather marked 
deficiency in precipitation during the past 15 years in the eastern portion 
of the United States. 

St. Mary's County receives annually slightly over 41 inches of rain- 
fall. The gTeatest average occurs in July, with 4.45 inches, which is 
11 per cent of the annual total, and the least falls in December, with 
2.79 inches, which is 6 per cent of the annual amount. The precipitation 
is small and nearly equal in amount during January, June, and Novem- 
ber. The uniformity in the distribution of rainfall is thus notable. 
Tables IX, X, XI, XII, XIII, and XVI contain the monthly and annual 
precipitation at all stations. 

TABLE IX. 

PRECiriTATION AT ClIERKYPIELDS, 1893-1899. 



Y'ear. 


5 

•-I 




.a 


<1 




P 
a 


3 

►-5 


^ 
^ 




o 

O 


> 

o 




s] 

p 
p 
p 

< 


1893 








1 










6.40 8.27 3.34 
3.29 , 2.38 2.85 

S 07 o -ifl ' 1 11'} 




1894.... 

1895 


3.10 
2.98 
1.24 
1.92 
l.f)3 
2.96 


4.00 
1.78 
4.92 
6.59 
1.46 


1.23 
3.65 

2.80 
5.05 
4.47 


3.1fi 
4.51 
1.02 
2.73 
3.48 


3.85 
4.90 
f).24 
3.83 
4.49 


1.90 

2.38 
3.39 
2.82 
2.96 


3.. ^2 
7.08 
8.56 
2.78 
7.04 


3.20 
2.29 
0.79 
3.96 
6.56 


3.69 
1 12 


34.17 

38.45 


1«9R 


3.47 1.40 2-28 


1.40 


37. ''1 


1«97 


0.68 ; 6.53 1.72 
2.31 3.29 ! 2.29 


2.78 
2.83 


38.28 


1898 


43.38 


1899 














3.69 













Means 


2.14 3.55 


3.42 


2.98 


4.26 


6.04 


3.36 


2.23 


3.83 3.23 


8.52 1 40.25 



MARYLAND GEOLOGICAL SURVEY 



159 



TABLE X. 

Precipitatiox at Porto Bello, Md. 



Year. 


a 

1-5 




.a 

o 


< 


a! 


d 
a 

1-5 


3 

1-5 


3 


ft 


o 
O 


> 

o 

12; 


d 


a 

3 

a 
c 
< 




2.82 


3.49 




3.99 


3.65 


5.42 


6.14 


4.21 


2.52 





















TABLE XL 
Monthly Precipitation at Leonardtown, Md. 



Year. 


c 

1-5 


® 

fa 


.a 
p 

3 


< 


OS 


2 

3 
1-5 


J-uly. 
Aug. 


ft 


4J 

o 

o 


c 


d 
Q 


"5 

c 
< 








1 








5.27 


0.05 




1.30 


4.40 


2.73 


3.25 '< 4.30 



















2.46 6.17 


2.64 10.32 


1 0.74 1 1 2.63 

1.21 i 2.29 i 1.13 5.31 




J892 


2.95 4.09 


5.08 1 4.38 


2.50 ; 












_ 

















Year. 



1861.... 
1862.... 
1863. . . . 
1864.... 
1865.... 
1866. . . . 
1867.... 
1868. . . . 
1869.... 
1870.... 
1871.... 



Means. 



TABLE XII. 
Precipitation .at St. Mary's, Md., 1861-1871. 



.29 



4.20 
2.53 
1.12 
4.55 
4.17 
2.45 



3.55 



J 






^ 


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>> 


03 


ft 


33 


S 


< 


s 



2.11 

4.45 
5.14 
1.20 
2.88 
4.26 



2.25 
3.79 



2.60 
5.56 
2.36 
3.56 



3.81 
0.84 

i6!87' 

, 3.69 

4.59 



3.41 ! 4.26 



6.98 
5.32 
3.50 
6.56 
3.48 
3.55 
1.56 
1.75 
3.85 



4.06 



4.47 
4.87 
3.75 
2.83 
3.13 
4.. 59 
5.56 



3.16 
4.38 
3.18 
1.19 



3.73 
4.00 



4.03 



3.17 



5.49 
0.93 



2.55 



3.61 



14.98 
3.90 
0.37 
5.05 
3.55 



5.35 



5.20 
3.64 
3.26 
2.85 
0.63 



1.33 
6.15 



3.01 



3.93 
3.45 
3.56 
1.98 
3.95 



4.33 
0.68 
3.50 



2.78 



3.40 
3.20 
3.85 
2.30 
5.55 



3.95 
2.51 



3.39 



0.84 
3.50 
3.50 
1.85 
4.31 



2.90 
3.38 



3.91 



.57.42 
44.85 



43.53 



Greatest amount. 
Least amount 



5.08 5.56 
1.12 1.20 



10.87 
0.84 



5.56 

2.75 



4.38 
1.19 



0.93 



14.98 
0.27 



6.15 
0.62 



4.33 
o!68 



5.55 
3.30 



4.31 

0.84 



57.43 



IGO 



THE CLIMATE OF ST. MARY S COUNTY 



Excessive precipitation (10.00 inches or more in one month) does 
not occur frequently in St. Mary's County. Omitting the doubtful 
record of 1872 for St. Inigoes, it appears that the following large amounts 
have been recorded: Leonardtown, 10.32 inches, July, 1891; St. Mary's 
City, 10.87 inches, in March, 1867, and 14.98 inches in August, 1861; 
St. Inigoes, 15.15 inches in August, 1873, 12.95 inches in April, 1874, 
and 11.01 inches in August, 1875. At all stations amounts less than 1.00 
inch frequently occur. The lowest record for each station is : Charlotte 

TABLE XIIL 
Precipitation at St. Inigoes, Md., 1871-1879. 



Year. 




Feb. 
March. 


< 


>> 

S3 


6 
a 

3 


3 


Sib 

3 
< 


D. 


o 
O 


i 

iz; 


6 
o 
O 


a 

3 
C 

< 


1871 


1 






1 




5.08 
7.50 
5.50 
7.76 
1.45 
6.10 
4.05 
0.76 




6.R9. 


1 
5.64 


1872 

1873 


0.63 
3.63 
4.40 
4.25 
1.20 
0.95 
2.40 
2.80 


8.75 112.80 
7.67 1 1.86 
4.75 ! 3.65 
3.45 fi.a.'i 


3.70 

1.45 

12.95 

2.75 
2.45 
3.40 
2.90 


9.82 
4.20 


1.80 10.60 
n.m 1 fin 


10.30 
15.15 
1.10 
11.35 
2.35 
1.00 
4.50 


11.01 5.00 
6.50 ! 2.77 
0.25 ' 1.25 
1.15 '^-fUl 


6.70 88.51 


1874 


2.65 1 1.55 3.10 
1.30 3.70 3.00 
4.65 , 2.76 2.65 
2.55 i 1.85 , 3.20 
4.80 2.70 1.75 


3.35 64.65 


1875 


3.00 46. R5 


187fi 

1877 

1878 

1879 


2.85 
1.05 
1.80 
2.20 


5.15 
3.30 
2.50 


1.00 
3.60 
2.15 


3.55 
3.40 


1.15 43.35 
1.20 29.70 
2.60 33.16 




















i 




2.52 


4.06 


4.94 


4.23 


4.27 2.12 


3.67 


6.64 


4.77 


3.67 


3.44 


3.36 


47.59 






Greatest monthly 
Least monthly.... 


4.40 
0.53 


8.75 
1.05 


12.80 
1.86 


12.96 
1.45 


9.82 
1.30 


3.70 
0.50 


10.60 
1.50 


15.15 
1.00 


7.75 
0.76 


11.01 
0.25 


6.62 
1.25 


6.70 
1.15 


8.'«.51 
29.70 



Hall, 0.10 inch, February, 1901 ; Cherryfields, 0.58 inch, in September, 
1897; Leonardtown, 0.05 inch, in December, 1889; St. Mary's, 0.27 inch, 
in August, 1863, and St. Inigoes, 0.25 inch, in October, 1874. The 
difference between the spring and summer rains is not very great, and 
autumn and winter are likewise very close. 

The figures given in the precipitation tables show that while insufficient 
rainfall for the requirement of crops is likely to occur during almost any 
month of the growing season, an entire failure of crops on account of 
drought is impossible; at no station are two months in succession found 
with less than one inch of rainfall, and usually the amount is abundant 
at all seasons of the year. The summer months are likely at all times 
to show a greater variability in amount than the winter months, because 
the rainfall of summer is usually in the form of local showers or thunder- 



MARYLAND GEOLOGICAL SUKVEY 161 

storms, which often occasion heavy downpours over limited areas during 
brief periods of time, while in winter, rains are general over the State, 
and are necessarily less in amount. 

For further details in regard to the climate of St. Mary's County, 
reference is made to the following brief sketch of the Climatology of 
Charlotte Hall. 

THE CLIMATOLOGY OF CHARLOTTE HALL 

Latitude, 38° 28' N.; longitude, 76° 47' W.; elevation, 167 feet. 
Observer, Prof. J. Francis Coad, 1893 to 1904. 

INTKODUCTORY. 

The station is situated in the northwest portion of St. Mary's County 
in the region of the greatest elevation of the land, on the line of the 
Washington, Potomac, and Chesapeake Eailway. It is on a level plateau 
of considerable extent, l3ang between the headwaters of Trent Hall Creek 
and Gilbert Swamp, An exact description of the position of the instru- 
ments cannot be given ; they were probably suitably located in the vicinity 
of the school in which Prof. Coad was an instructor. At present the 
instruments are exposed in a standard shelter in the garden south of 
the rectory of Trinity Glebe, about two miles from Charlotte Hall. The 
shelter is over sod, and the door opens towards the north ; the thermome- 
ters are about 4 feet from the ground. The nearest woods are about 
400 feet south of the shelter, and there are no large bodies of water in the 
vicinity. 

For the convenience of the investigator it is advisable to adopt a 
uniform method of presenting the statistical material available for im- 
portant individual stations, where this is possible. For Charlotte Hall 
records are available for 109 months, or 9 years, but observations were 
not continuous throughout each year, except in 1895, 1897, 1898, and 
1900. The main features of the climate of this station are presented 
in the meteorological summary by months in Table XIV. Other details 
are given in the usual manner, in Tables XV to XXIII. 



lG-3 



THE Cl.niATH OK ST. .MAltV S COLNTY 



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MARYLAND GEOLOGICAL SURVEY 



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164 



THE CLIMATE OF ST. MARY's COUNTY 



THE TEMPERATURE CONDITIONS. 

Attention has already been invited to the fact that the mean tem- 
peratures for Charlotte ITall, during the period from 1892 to 1904 can- 
not be considered as normal for the region ; they represent the conditions 
prevailing during a period which careful examination shows to have 
been deficient in temperature as compared with the true normal. The 

TABLE XV. 
Monthly and Annual Mean Temperatures at Charlotte Hall, Md., 1892-1905. 



Year. 



1893. 
1893. . 
1H94. . 
1895.. 
1896. . 
1897. . 
1898. . 
1899. . 
1900. . 
19ni.. 
1902.. 
190.3. . 
1904.. 
1905.. 



31.0 



29.8 



37.7 



38.6 


,36.0 


32.8 


25.8 


33.6 


36.8 


33.2 


37.4 


38.3 


35.6 


31.2 


29.6 


36.3 


34.2 


34.4 


31.8 


31.6 


29.1 



48.7 
43.2 
39.2 
47.0 
49.0 
44.3 
39.6 
45.8 



52.0 



43.3 



52.2 
64.2 
57.8 
54.6 
51.2 



53.3 
49.8 



62.5 
69.7 
63.6 
64.8 
64.7 
64.2 
63.0 
6.40 



51.9 65.0 



76.5 
73.6 
75.3 
70.8 
69.7 
73.0 



72.0 



77.6 
73.4 

77.0 
76.0 
78.1 



78.6 



75.0 
74.2 



73.8 
76.4 

75.7 
81.8 



73.8 





















« 


• 








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ft 


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B 








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73.8 



69.4 
71.5 
66.6 
74.3 



66.2 



56.6 
58.0 
51.0 
55.. 'S 
59.0 
58.3 
68.9 
63.2 
54.6 
68.8 
57.4 



44.6 
44.0 
46.0 
54.0 
48.5 
45.1 
45.6 
49.2 



39.7 
43.0 



39.5 
37.6 
38.0 
38.4 
41.4 
34.2 
41.6 
36.0 
3; J. 8 



30.7 



54.6 



56.1 
56.3 



56. 



Means. 



34.0 



33.4 



44.5 



53.0 64.6 



73.0 



77.0 



76.3 



70.6 



57.4 



46.0 



37.1 



65.6 



Highest Means....! 38.6 37.7 49.0 57.8 69.7 76.5 78.6 

Lowest Means 29.8 26.8 39.2 49.8 62.5 69.7 73.4 

Range i 8.8 111.9 9.8 8.0 7.2 6.8, 5.2 



81.8 74.3 63.2 54.0 41.6 56.9 
73.8 66.2 51.0 39.7 30.7 54.6 j 
8.0 I 8.1 , 12.2 14.3 10.9 3.3 



deficiency resulted from the occurrence of several severe winters in rapid 
succession, namely, in 1895, 1899, and 1904. 

The annual mean temperature at Charlotte Hall is 55.6°; this is 1.1° 
lower than the mean for Solomons, which is farther south and nearer 
the waters of the Bay. The variation in the monthly mean tempera- 
tures is considerable. The coldest month is February, with a mean of 
33.4° ; the warmest is July, with 77.0°, giving a mean annual range of 
43.6°. February in 1895, 1899, and 1902 was very cold. The variations 
in the monthly means during warm summers and cold winters are better 
adapted to show the possible fluctuations in temperature in this region. 
In August, 1900, the mean temperature at Charlotte Hall was 81.8°, 



MARYLAND GEOLOGICAL SURVEY 



165 



the highest mean on record. The lowest, 25.8°, occurred in February, 
1895, giving a range in monthly means of 56.0°. 

TABLE XVI. 

Highest Temperatures at Charlotte Hall, Md. 



Year. 


a 

53 

t-5 




J3 


a. 
< 


a 


June. 
July. 


< 


0. 

01 






> 


2; 





OS 

3 

d 
a 
< 


1893 












100 
99 

'89'" 
92 
98 


100 
98 
94 
95 
90 

103 


96 
95 
99 
98 
90 
97 
97 
103 


'99" 

100 

"92' " ' 

99 
95 
100 


77 
85 
76 
85 
88 
88 
83 
90 
83 
81 
89 


73 
70 

78 

77 
78 
74 
73 
78 
84 

'77'" 


68 
58 
68 
70 
70 
61 
67 
65 
66 

■53 " 


100 


1894 

1895 


58 
62 
59 
64 
66 
60 
66 
68 
52 


68 
65 
64 
63 
70 

"to" 

61 
61 


83 
70 
70 
80 
81 
75 
69 
78 


84 
87 
97 
90 
86 

'si'" 

82 


'95" 
95 
85 
94 
92 
95 
88 
90 


99 
100 


1896 


98 


1897 

1898 


92 
103 


1899 




1900 


95 


100 


103 






1903 

1903 




100 
95 


•95 


'96' " ' 


100 


1904 


64 


61 


74 


82 


91 






















Means 


61.9 


65.8 


75.6 


86.5 


91.7 


95.6 


97.1 


96.6 


95.0 


84.1 


75.2 


64.6 


82.5 




68 
1901 
9 


70 

1898 
121 


83 

1894 
191 


97 
1896 
19 


95 
1895 
311 


100 
1893 
20 


102 

1898 
3 


102 
1900 
11 


100 
1895 
191 


90 
1900 
6 


78 
1895 

1 ^^' 


70 
1896 

71 


102 


Year 

Date 


1898 
31 



* On other dates also. 



TABLE XVII. 
Lowest Temperatures at Charlotte Hall, Md. 



Year. 


a 

8S 
1-5 




2 

03 


p. 

< 


08 


a 
3 
1-5 


3 
1-5 


bo 

3 
< 


4J 

P. 

m 





> 

12; 


6 

<a 


a 

3 
3 
3 
< 


1 893 












51 

41 

'49"" 
45 

48 


49'" 
53 

55 
58 
49 


53 
52 
52 
52 
57 
55 
57 
55 


'47'" 
44 

'43 " 
40 
39 
42 


29 
33 
23 
33 
36 
28 
27 
30 
30 
27 
33 


18 
20 
22 
29 
24 
23 
22 
93 

19 
16 


5 

13 
14 
14 
10 
14 
11 

■9" 




1894 


17 

10 
5 
5 

19 

- 1 

7 

8 

11 


15 
- 5 

5 
16 

3 

-19 

3 

10 

1 


15 
22 
13 

26 
21 

18 
11 

18 


26 
29 
25 
32 
25 

'27* ' ' 
29 


38" 

38 

42 

37 

36 

35 

.39 

38 


7 


1895 


- 6 


1896 


5 


1897 

1898 


5 

2 


1899 


-19 


1900 


50 


55 


8 


1901 


3 


1902 

1903 




56 
42 


53 


'46' ' ' 


1 


1904 


3 


- 4 


20 


25 


41 




- 4 










i 










8.4 


2.4 


18.2 


27.3 


38.2 


47.3 


50.2 


54.0 


42.1 


29.8 


21.6 


9.9 


29.1 








- 1 

1899 

2 


-19 

1899 

11 


11 

1900 
18 


25 
1896 
91 


35 
1900 
10 


41 

1894 
1 


42 
1903 
17 


53 

1894 

221 


39 

1899 
28 


23 

1895 
29 


16 

1903 

261 


3 

1901 
22 


-19 


Year 

Date 


1899 
Feb. 11 







1 On other dates also. 



The mean temperature of spring is 54°, of summer, 75° ; autumn, 
58°, and winter, 38°. Here also autumn is 4° degrees ' warmer than 
spring. 



16G 



THK CI-IMATK OF ST. MARYS COUNTY 



Tables Will and XIX give the means nf the niaxinuun and mini- 
nuini tomjieratures at Charlotte Hall. The mean niaximiun temperature 




Fig. 9. — Temperature curves for Charlotte Hall, (a) mean maximum, (b) 
average, (c) mean minimum. 

is found to be ()G.4°, the nienn iiiiniiiiuni. 1 l.T : Iherefore the mean 
daily range of temperature is •^1.1°. The nu'nii inaxiinuin temperature 
occasionallv exceeds 90° and ivached llie rather high iigure 95.1° in 



MARYLAND GEOLOGICAL SURVEY 



167 



August, 1900, but the record for that month is somewhat incomplete. 
Mean minimum temperatures below 20.0° were recorded in February, 
1895 (mean 16.3°), and February, 1899 (mean 17.6°). 



TABLE XV^III. 
Mean Maximum Temperatures at Charlotte Hall, Md. 



Year. 



1893. 
1894. 
189.5. 
1896. 
1897. 
1898. 
1899. 
1900. 
1901. 
1902. 
190.3. 
1904. 



Means. 



47.3 
41.2 

42.0 
41.6 
47.0 
4.5.4 
47.1 
45.8 
41.3 



39.7 



43.8 



44.7 
35.4 
47.3 
45.0 
47.8 
41.5 
45.6 
43.4 
36.9 



59.9 
53.5 
49.8 
57.1 
59.9 
54.7 
.50.9 
57.0 



63.5 

64.8 
70.3 
65.4 
63.7 



65.6 
60.1 



53. 



63.6 



43.0 



55.1 



73.3 

81.3 
73.6 
76.1 
77.1 
78.8 
74.4 
76.5 



88.8 
87.1 

'so! 6 

79.0 
85.9 



77.9 
76.5 



89.4 
84.6 
85.6 
84.1 
89.1 

"96'. 9 



87.5 



84.3 
91.0 

86.9 
83.8 
89.0 
85.8 
95.1 



81.8 
86.0 

85.0 
79.0 
86.4 



85. 



66.3 
68.3 
64.4 
65.3 
67.5 
70.7 
71.1 
74.8 
68.1 
69.8 
68.3 



.53.4 
53.4 
.55.9 
64.4 
58.4 
56.3 
58.6 
60.5 
50.5 



50.1 
46.4 
48.7 
49.3 
50.4 
45.0 
53.5 
48.3 
45.0 



87.5 I 83.4 



55.4 



40.5 



56.6 



47.7 



£5.4 
67.9 



69.0 



Highest Mean. 
Lowest Mean.. 
Range 



47.3 


47.8 


59.9 


70.3 


81.3 


88.8 


90.9 


95.1 


39.7 


35.4 


49.8 


60.1 


73.3 


79.0 


84.1 


83.8 


7.6 


12.4 


10.1 


10.3 


8.1 


9.8 


6.8 


13.3 



86.4 
78.9 
7.5 



64.4 
10.4 



64.4 
50.5 
13.9 



53.5 
40.5 
13.0 



■1.7 
61.5 
10.3 



TABLE XIX. 

Mean Minimum Temperatures at Charlotte Hall, Md. 



Year. 







^ 






c; 


a3 


0) 


eS 



> 


d 





<u 


IS 


P 



1893. 
1894. 
1895. 
189R. 
1897. 
1898. 
1899. 
1900. 
1901. 
1903. 
1903. 
1904. 



30.0 
24.4 
25.2 
34.7 
39.6 
33.9 



25.5 
23.1 
32.1 



Means. 



20.0 



24.8 



27.3 
16.3 
26.4 
29.8 
23.4 
17.6 
23.8 
31.1 
31.3 



33.9 



37.5 
33.0 

38.7 
37.0 
38.2 
33.8 
38.4 
34.7 



33.8 



33.9 



40.9 
43.7 
45 4 
43.9 
39.7 

'4i!6' 
39.5 



41.2 



41.9 



58.8 
58.1 
53.5 
53.5 
53.3 
49.7 
51.6 
51.6 



64.3 
60.2 



61.6 
60.4 
60.2 

'60.3 



53.2 



53.5 



65.7 
63.3 
68.4 
68.0 



67.3 
58.1 



65.4 



63.4 
63.6 
66.4 
66.6 
64.9 
63.9 
65.6 
68.6 



63.0 



65.0 



63.5 
61.5 

'.59!.3 
58.0 
54.3 
63.3 



53.6 



47.8 
37.7 
45.7 
50.5 
45.9 
46.9 
51.6 
41.3 
47.7 
46.6 



46. S 



35.9 
.35.7 
36.3 
43.5 
38.6 
34.0 
33.6 
38.0 
38.9 



).5 



35.4 



38.9 
37.4 
37.5 
33.4 
33.4 
29.6 
33.8 
33.6 



30.9 



27.5 



44.8 



44.7 



Highest Mean. 
Lowest Mean. 
Range 



30.0 
30.0 
10.0 



29.8 
16.3 
13.5 



38.3 
28.4 



45.4 

39.5 49.7 

5.9 9.1 



64.3 
60.2 
4.0 



68.4 
58.1 
10.3 



63.0 
6.6 



63.5 
53.6 



51.6 
37.7 
13.9 



43.5 38.9 
38.9 30.9 

14.6 18.9 



50.0 
39.6 
10.4 



The curves of mean temperature and of mean maximum and mean 
minimum for Charlotte Hall are given in Fig. 9, Avhich conveniently 
shows the range in averag-e values for this station. 



168 



THE CLIMATE OF ST. MARY S COUNTY 



The extremes of temperature are sliglitly greater in this section of 
the country than farther south. It is to be observed that a comparison 
of the extremes at Baltimore and at most co-operative stations is scientifi- 
cally not admissible; the thermometers at Baltimore are placed 80 feet 
above the ground, while at nearly all co-operative stations they are at 
an average elevation of about 5 feet. The extremes both of summer 
heat and winter cold are diminished with elevation above the earth's 
surface, although the mean temperature between 5 and 60 feet will 



TABLE XX. 



Number of 


Times Maximum Temperatures was above 


90° and Minimum below 


32"' 






AT Charlotte 


Hall, Md. 












Maximum Temperature above 90°. 




Minimum 


Temperature bel 


ow 33<>. 












■w 




"3 


















•5 


1^ 

at 


>> 


V 


t^ 


be 


4J 

a. 


s 


h 
cj 




> 


o 


Q 


.0 


2 


'u 


3 
C 


« 


a 


3 

"-5 




s 


a 


4) 


o 




o 













fH 


g 


1-5 


< 


CO 


< 


>> 


O 


'^ 


Q 


1-5 


W 


S 


< 


< 


1894 . . . 




12 16 
5 


6 
18 


4 
10 




1894 . . . 

1895 . . . 




8 


12 
12 


19 
19 


17 
26 


20 
25 


9 
14 


8 

3 


80 


1895 . . . 


3 


106 


1896 . . . 





R 


11 








1896 . . . 

1897 . . . 






5 
6 


20 
14 


25 
25 


17 
16 


19 
5 


6 



91 


1897 . . . 


1 





2 


3 


66 


1898 . . . 




in 


11 


13 


10 


45 


1898 . . . 


2 


12 


23 


18 


23 


12 


8 


98 


1899 . . . 


3 
6 






7 


14 




1899 . . . 

1900 . . . 


1 


16 
9 


"27" 


26 


22 
19 


9 
18 


" 3 




1900... 




16 




1901 . . . 
















1901 . . . 
Means 


1 


20 


20 




23 


11 


1 
















Means 


i 


8 


9 


9 


7 


37 


2 


11 


20 


23 


21 


12 


3 


92 



hardly vary a tenth of a degree (Hann). On clear, cold nights the 
temperature at 5 feet elevation may be from 5° to 10° lower than it is 
at 80 feet. The minimum temperatures in winter are lower at co- 
operative stations than would appear to be correct if comparison be made 
with the temperatures recorded at Baltimore. 

During the past few years the range of extremes at Charlotte Hall, 
in common with most other stations in Maryland has been quite remark- 
able. The summer of 1900 was one of extraordinary warmth throughout 
the eastern United States, while the preceding February (1899) was 
extremely cold. During the warm wave of August, 1900, the maximum 
at Charlotte Hall reached 102°, on the 11th; while during the cold wave 
of February, 1899, the lowest temperature was 19° below zero, the 
ground being covered with snow. During this cold wave the lowest tern- 



MARYLAND GEOLOGICAL SURVEY 



169 



perature recorded in the historj- of the Baltimore station occurred on 
the 10th, 7°. below zero. On this occasion there was consequently an 
inversion of temperature (a rise of temperature Avith elevation instead 
of the normal fall) showing that the cold air occupied a relatively thin 
layer near the ground. j\Iaximum temperatures above 100° are not very 
frequently observed at Charlotte Hall, though this figure was reached once 
in June and once in July, 1893, also in July, 1898, 1900, 1902, and in 



Au3. 
/as 

/oo 
95 
30 

o- 8? 
C' 

80 


S 6 7 & B 10 /I /z /3 1^ isX 


























































I ■ 




























































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i 










































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, 






















































/ 










N 


















- 
































/ 














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\ 


























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■^ 












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/ 
















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/ 












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L 














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r 


















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f 










































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__ 




_ 


— 


























J 








1 1 


-L. 





Fig. 10.— The warm wave of August, 1900, at— (a) Charlotte Hall, (b) Grants- 
. ville, (c) New Market. 

September, 1900. Temperatures below zero were also experienced in 
February, 1895 (5° below zero on the Gth), and in January, 1899 (1° 
below zero on the 2d). 

Duration of ^Yarm Waves. 
The maximum temperature exceeds 90° on the average 37 times per 
annum at Charlotte Hall; at Solomons only 20 times, showing the in- 
fluence of the inland location of the former station. The record of 
maximum temperatures is somewhat broken, so that the following table 
of dates, on which the maximum was 95° or above, is not complete. 
12 



170 THE CLIMATE OF ST. MARY's COUNTY 

Dates on wliicli the teinperaturo Avas 95° or above at Charlotte Hall: 

1893.— June 4, 5, 10, 19, 20, 25;' July 2, 8, 12, 13, 14, 15, 26, 30;' August 25. 

1894.— June 23, 24, 25; July 12, 13, 14, 19, 20, 2G, 27, 29; August 9; Septem- 
ber 9, 10. 

1895.— May 31; June;' August 9, 10, 11, 12, 15, 16, 24, 28, 29, 30; September 
12, 19, 20, 21, 22, 23. 

1896.— May 9, 18, 19; July 27; August 5, 6, 7, 8, 9, 10, 11, 12, 13. 

1897.— None. 

1898.— June 12, 25, 26, 28; July 1, 2, 3, 4, 18, 19, 20, 29, 30; August 1, 2, 3, 4, 
7, 8, 23, 31; September 1, 2, 3, 4, 5, 6, 7, IS. 

1899.— June;' July;' August 5, 20, 21; September 6. 

1900.— May 15; June 3, 4, 5, 6, 7, 8, 15, 16, 17, 18, 19; August 6, 7, 8, 9, 10, 
11, 12, 13, 14, 26, 27;' September 1, 5, 6, 7, 8, 9, 10, 11. 

1901 to 1904.' 

' Record Incomplete. 

The actual record for the August, 1900, " hot wave/' Gth to 1-lth, is 
represented in comparison with other stations in Fig. 10. The tempera- 
tures recorded were: (Uh, 96°; 7th, 98°; 8th, 97°; 9th, 96°; 10th, 99°; 
11th, 102°; 12th, 101°; 13th, 96°; 14th, 9-5°. The September record 
was also rather remarkable, viz.: September 5th, 95°; Gth, 96°; 7th, 
100°; 8th, 98°; 9th, 95°; 10th, 96°, 11th, 99°. 

Duration of Cold Periods. 

The miuiniuni temperature at Charlotte Hall falls below the freezing 
point of water on the average 92 times in the year, as compared with 
68 times at Solomons. During the cold winter of 1895 it was below 
freezing 106 times. The average number of times with a minimum 
below 32° is 20 days in December, 23 in January, and 21 in February. 
The frequency of freezing temperatures in April and October is also 
slightly higher than for other portions of the county^ 

The following record of the dates on which the miiiiniuiu temperature 
was below 20° is also somewhat incomplete. 

Days on which minimum temperature was below 20° at Charlotte 
Hall : 

1893.'— December 2, 3, 5, 14, 21. 

1894.— January 13, 28; February 2, 5, 6, 17, 24, 25, 28; March 27, 28; Novem- 
ber 29; December 28, 29, 30. 

1895.— January 1, 2, 5, 13, 14, 20, 24, 25, 30; February 1, 3, 4, 5, 6, 7, 8, 9, 10, 
11, 12, 13, 14, 17, IS, 23, 24; December 4, 6, 12, 13, 14, 15, 16, 17. 

' Indicated record incomplete. 



MARYLAND GEOLOGICAL SURVEY 



171 



1896._January 2, 4. 5, 6, 7, 11, 12, 15, 16; February 17, 18, 19, 20, 21, 22, 26; 

March 13, 14, 25; December 3, 4, 5, 22, 23, 24, 30. 
Ig97._january 7, 8, 9, 13, 25, 26, 27, 28, 29, 30, 31; February 1, 28; December 

24, 25. 
1898 —January 2, 4; February 1, 2, 3, 4, 5, 7, 17, 26, 27; December 2, 8, 9, 10. 

12, 13, 14, 15, 16. 
1899.— January 1, 2, 3, 8, 11, 19, 20, 27, 28, 29, 30, 31; February 1, 2, 3, 8, 9, 

10, 11, 12, 13, 14, 15, 25; March 6, 8, 9; December 7, 17, 21, 26. 




Fig. 11. — Minimum temperatures during the cold waves of February, 1895, and 
1899, at— (a) Charlotte Hall, (b) Deer Park. 

1900.— January ^ 2, 3, 27, 29, 31; February 1, 2, 3, 18, 19, 20, 25, 26, 27, 28; 
March 12, 13, 17, 18, 22; December 11, 12, 14, 15, 16, 17, 21, 22, 
28, 29. 

1901.— January^ 3, 4, 5, 6, 13, 18, 19, 20; February 1, 2, 6, 7, 8, 11, 12, 13, 14, 
19, 20, 21, 23, 25, 28;' March 6; November 20, 21, 22, 28, 29; Decem- 
ber 4, 5, 6, 7, 8, 15, 16, 17, 18, 19, 20, 21, 22. 

1902.— January ' 7, 13, 14, 15, 17, 19, 20, 27 28, 29, 30, 31; February' 3, 4, 5, 
6, 8, 9, 11, 12, 13, 14, 15, 19, 20; December.' 

1903.1 

1904.'— January ' 3, 4, 5, 6, 8, 10, 12, 15, 18, 19, 20; February;' March 5, 29. 

' Record incomplete. 



172 



THE CLl.MATE UF ST. MARY S COUNTY 



The longest consecutive period of cold weather occurred in February, 
1895; during that month the tenii)erature was 32^ or below on 25 days, 
and 20° or below from the 3d to 15th, as follows: 

3d, 6° ; 4th, 1-4° ; 5th, 5° ; 6th, — 5° ; Tth, 8° ; 8th, 1° ; 9th, 5° ; 10th, 
10° ; 11th, 9° ; 12th, 10° ; 13th, 18° ; 14th, 11° ; 15th, 12°. The follow- 
ing is the record for the cold wave of February, 1899 (temperatures 2.0° 
or below) : 8th, — 1° ; 9th — 16° ; 10th, — 17° ; 11th, — 19° ; 12tli, 4° ; 
13th, 5°; 14th, 4°; 15th, —2°. 

These two remarkable cold waves are illustrated graphically in Fig, 11. 

Duration of the Crop Season. 

The date of the last killing frost in spring averages somewhat later 
than at Solomons, the mean for eight years being April 15; the 
average date of the first killing frost in autumn is October 17, 27 days 
earlier than at Solomons. While the record for Charlotte Hall is not 
very complete, the figures, nevertheless, indicate that the proximity of 
the waters of the Bay lengthens the growing season, which is 6 months 
and 2 days at Charlotte Hall, as compared with 6 months and 21 days 
at Solomons. A light frost has occurred at Charlotte Hall as late as 
May 26 (1899), with a minimum temperature of o6°. The earliest 
light frost was apparently tliat of September 30, 1895. 

The following table gives the dates of the first and last killing frosts 
as far as available : 





Killing Frosts. 






Last in Spring. 


First In Autuniii. 


1803 






October 17. 


1894 


April 


12. 


October 15. 


1895 


April 


12. 


October 10. 


1896 


April 


9. 


October 25. 


1897 


April 


21. 


November 13. 


1898 


April 


28. 


October 24. 


1899 






October 2. 


1900 


April 


15. 


October 17. 


1901 


April 


5. 


October 16. 


1902 






October 30. 


1903 






October 27. 


1904 


April 


22. 





MARYLAND GEOLOGICAL SURVEY 



173 



PRECIPITATION. 

The exigencies of Prof. Goad's private affairs necessitated his frequent 
absence from station, with the unfortunate result that the records of 



TABLE XXI. 
Monthly and Annual Precipitation at Charlotte Hall, Md., 1892-1904. 



Year. 



1893. 
1893. 
1894. 
1895. 
1896. 
1897. 
1898. 
1899. 
1900. 
1901. 
1903. 
1903. 



4.03 

3.11 
3.63 
1.89 
1.75 
3.30 
4.15 
3.54 
3.43 
3.45 



1904. 



Means 3.13 



3.46 
1.38 

4.87 
5.03 
1.10 
5.75 
4.44 
0.10 
3.19 



3.76 4.47 



3.26 



0.91 
3.28 
3.82 
3.53 
4.33 
4.61 
3.05 
2.40 



3.10 
6.65 
1.03 
2.33 
3.43 



3.55 
7.08 



3.54 



3.02 



3.15 



4.68 
1.16 
4.69 
4.98 
3.21 
1.79 
4.70 
3.69 



1.06 
1.15 
3.99 
4.38 
2.69 
1.76 

h'.is 



1.52 



3.38 



3.66 
2.91 
3.25 

3.83 
6.78 
4.37 

'h'.'d' 



3.61 



1.48 
3.79 
1.59 
0.94 
3.04 
4.00 
5.53 
3.07 



•4.09 



3.69 



3.04 



0.95 
1.69 
4.36 
4.79 



2.03 



2.64 



4.48 
•*.15 
3.65 

6!31 
3.96 
4.39 
3.63 
0.98 
4.33 
4.89 



1.65 
2.20 
1.08 
3.19 
2.40 
1.41 
1.89 
1.53 



^,26 



1.85 



4.10 



3.33 



42.16 
36.94 



40.26 



36.79 



Greatest amount. 
Least amount — 
Difference 



4.15 
1.75 
3.40 



5.75 
0.10 
5.65 



4.61 


7.08 


4.98 


5.18 


6.78 


5.58 


4.79 


6.31 


3.19 


4.10 


0.91 


1.03 


1.16 


1.06 


3.83 


0.94 


0.95 


0.98 


1.08 


0.34 


3.70 


6.05 


3.82 


4.13 


3.96 


4.64 


3.84 


5.33 


2.11 


3.76 



7.08 
0.10 
6.9S 



TABLE XXII. 

Greatest Precipitation in 24 Hours at Charlotte Hall, Md. 



Year. 



•^ —• 



S ri 



1893. 
1894. 
1895. 
1896. 
1897. 
1898. 
1899. 
1900. 
1901. 
1903. 
1903. 
1904. 



1.00 
1.02 
1.57 
1.04 
0.76 
1.16 
1.13 
3.10 
1.25 



1.07 
0.50 
1.98 
1.60 
0.86 
3.00 
1.60 
0.10 
1.20 



0.26 
1.40 
1.00 
0.96 
0.92 
0.96 
0.50 
0.80 



0.67 



1.09 
3.67 
0.83 
0.75 
1.31 



2.15 
2.50 



1.50 



1.12 
0.30 
1.93 
1.52 
1.00 
0.68 
0.95 
1.52 



0.52 
0.60 

6.'7i' 
1.30 
0.54 



0.75 



1.80 
1.22 
0.90 
0.62 
1.42 
1.98 

2!72' 



0.80 



0.58 
1.08 
0.49 
0.35 
1.03 
1.74 
1.63 
1.38 



1.00 



0.59 



0.95 
1.45 
1.83 
2.40 



1.00 



2.02 
1.98 
1.28 

3!26 
0.73 
3.30 
1.85 
0.35 
1.63 
1.39 



0.50 
0.68 
0.96 
1.33 
0.69 
0.86 
1.00 
1.36 



0.83 



70 
3.00 
1.10 
0.24 
1.33 
0.80 
0.90 
1.95 
1.30 



3.00 
3.67 



2.20 
1.98 
3.00 

3.72 



Greatest AraouQt.! 2.10 i 3.00 

Year 1901 \ 1899 

Date 11 112-13 



1.40 

1895 

2 



3.67 

1895 

8 



1.93 

1897 
13 



3.56 
1900 
17-18 



1900 
13 



1.74 3.40 
1898 ; 1900 
13 15 



3.20 
1897 
35 



1..36 
1901 
23 



3.00 
1894 
26 



3.67 
1895 
Ap.8 



rainfall at the station are much broken, especiall}^ during tbe summer 
months. It is probable that the averages found are slightly too low 
even for the period covered; certainly the mean for August (2.69 inches 
for 8 months) is rather low. 



174 



THE CLIMATE OF ST. ilARY S COUNTY 



The precipitation for the interior of !St. Mary's County may be ex- 
pected to be soniewliat smaller than the a\fi'ai:c I'oi- the county, ami the 
record for Charlotte Hall may be accepted as faiily correct as a whole. 
The annual total for 9 years is 3G.79 inches. The complete record for 
Solomons gives 39.05 inches. The station has not received a total of 
10.00 during any month, the maximum record being 7.08 inches in 
April. 1901. Amounts less than 1.00 inch are not uncommon. The 
smallest total was 0.10 inch in Feljruary, 1901. 



TABLE XXIIL 
Monthly and Annual Snowfall (hnmelted) at Charlotte Hall, Md. 

































^ 




















OS 


Year. 


c 4 

at 1 ® 


o 


a 


as 




a 


>. 


b() 


s. 




> 

o 


6 


3 

C 




•4 P^ 


s 


< 


s 


<-> 


1-5 


< 


OQ 


® 


^ 1 


tt 


^ 


1H94 


T 7.5 





T 




















1 




4.0 


11.5 


],S95 


14.0 13.5 


T 























'J' 


3.5 


.31.0 


1890 


T T 


3.0 





(1 

















0..5 


1.0 


3.5 


LS97 


fi.5 7.0 





























T 


13.5 


1S9,S 


4.0 n*^ 



R.O 


T 




























2.0 



1.6 



7 7 


1899 


fi.n 


39.5 


51.0 


191)0 


1.0 


8.0 


3.0 























T 


3.0 


15.0 


1!)01 


T 
4 5 


T 


T 























T 


1.5 


1.5 


190"' 
















1 , 


Means 


4.0 8.8 


1.3 


T 




















0.4 


2.3 


16.7 






Greatest monthly 


14.0 


39.5 


6.0 


T 




















2.0 


4.0 


51.0 


Least monthly — 


T 


T 
































1.5 



The. largest average rainfall is found in July, when the normal is 
4.09 inelies, or 11 per cent of the annual total; the least occurs in 
November, with but 5 per cent of the annual amount. 

The record of average, maximum and niinimmn precipitation is shown 
graphically in Fig. 12. 

Excessive precipitation is even less frequent in the interior of this 
region tlian along the coast. At Cliai'lotte Hall a fall exceeding 2. .50 
inches in 24 hours has been recorded in February, 1899 (3.00 inches), 
in April, 1895 (3.G7 inches), in June, 1900 (2.5G inches), in July, 
1900 (2.72 inches), and in December, 1894 (3.00 inches). Heavier 
rains for brief periods were not recorded. 

The following were the longest periods of consecutive rainy days: 



MARYLAND GEOLOGICAL SURVEY 



175 



189G— May 19 to 26 (8 days), amount, 0.72 inch. 

1897— Jnly 16, 17, 18, 19. 20, 21, 23, 24, 26, 27, 28, 29 (5.78 inches). 
October 19, 21, 22, 23, 24, 25 (6 days), 5.22 inches. 

1898— August 4 to 12 (7 days), 3.94 indies. 

1901— April 19 to 25 (7 days), 1.45 inches. May 25 to 29 (5 days). 
2.25 inches. 

1903— October 6 to 11 (6 days), 3.79 inches. 

The maximum record is found for July, 1897, when 5.78 inches fell 
during 12 days, with an absence of rain during the period on the 22d 



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--I 


1 




_M 




— U- 




























































































































































































^ 






„ 


__ 


__ 


__ 




_ 


__ 




p 


~- 













J_ 







-- 




L 


' 








- 


- 






- 


- 


= = 


= 


i ~ 








- 


— 


— 










-— 




-- 






- 


-r- 






— 




















































! 






-«c 


1 






U" 


■■ 














































_L 






_ 














X. 














.. 








.- 


±. 









Fig. 12. — Precipitation for each month in the year at Charlotte Hall — (a) 
greatest, (b) average, (c) least. 

and 25th. On the other hand the greatest duration of consecutive days 
without precipitation was 31 days, from February 4 to March 4, 1901. 
Other long dry periods occurred in 1893, October 27 to November 20 
(24 days), and in 1896, April 2 to April 29 (28 days). 

Snowfall (Unmelted). 
The snowfall at this station does not greatly differ in amount from 
that received at Solomons; it occurs under similar circumstances, as 
regards the path of barometric depressions, and generally with winds 
in the northeast quadrant. The annual average is about 17 inches. 
The largest snowfall occurred in 1899, with 51 inches. The fall was 



176 



THE CLIMATE OF ST. MARY's COUNTY 



extremely large during Februaiy, 1899, which received 39.5 inches, of 
wliicli 30 inches are supposed to have fallen during 24 hours on the 
13th. Very little snow fell in 1896 (3.5 inches), and in 1901 (1.5 
inches). 

TABLE XXIV. 
Metkorological Stations in St. Mary's County. 



Stations. 


Observers. Period. 


w 
u 


Lati- 
tude. 


Longi- 
tude. 


Eleva- 
tion. 


Remarks. 


Charlotte Hall 


R.W. Sylvester 1892 

i'rof. .7. Francis Coad. . 1898-1904 
Rev.J.Neilson Barry. 1905 


9 
5 


38° 28' 


76° 47' 


Means from maxi- 
,/.., f^ mum and minimum 
^°' '■^- temperatures. Rec- 
ords broken. 


Cherry fields!.. 


Col. J. Edwin Coad .... 1893-1899 


38° 12' 


76° 32' 


Means from obser- 
7 ft. vationsat8a.ra.and 
8 p.m. 


Leonard town . 


Dr. Alex. McWilliams 
Geo W Joj' 


1858-1859 
1889-1893 


1 
3 

1 

1 


38° 18' 


76° 38' 


Smithsonian Insti- 
tution record. Ob- 
,K f ^ servationsat 7 a.m., 
50 ft: TiJ,"'}9p.m. nuvmg 








1893 trom maximum 
and minimum tem- 
peratures. 


Porto Bello.... 


Alpheus Hyatt 


1895 


38° 10' 


76° 26' 


Established Jan. 1. 
40 ft. 1905, by Md. State 
Weather Service. 


Ridge 


T. G. Staggs 1856-1857 


38° 7' 


76° 22' 


Smithsonian Insti- 
tution record. Ob- 




2 and 9 p.m. No 
rainfall. 


St. Iniyoes 


.Tames F. Ellicott 1871-1879 


38° 9' 


76° 23' 


Smithsonian Insti- 
,A f^ tution record. Ob- 
servationsat 7a.m., 
2 and 9 p.m. 


St. Mary's City 


Rev. Jas. Stephenson. 1S57-1870 


38° 11' 


76° 26' 


Smithsonian Insti- 
45 ft. tution records ; not 
continuous. 



1 p. O. Valley Lee, Md. 

AVINDS AND WEATHER. 

Tlic ])icvailing winds are from the northwest during winter in St. 
Mary's County, and from the west and southwest during summer months. 
The average number of clear days is fairly high. Specific data with 
regard to the number of thunderstorms, local wind storms, etc., are not 
available. 



THE HYDROGRAPHY OF ST. MARY'S 
COUNTY 

BY 

N. C. GROVER 

St. Mary's Count)- forms the peninsula of land projecting into Chesa- 
peake Bay, between the Potomac and Patuxent rivers. Although it is 
nearly surrounded by water, its hydrography is unimportant. Potomac, 
Wicomico, and Patuxent rivers, which, together with Chesapeake Bay, 
form its boundaries on all sides, except the northwest, are tidal streams 
within the limits of this county. The rise and fall of the tide, from 
Cohouck Point to St. Catherine Island, is about 1.9 feet; from St. 
Catherine Island to Point Lookout, 1.6 feet; from Point Lookout to 
Cedar Point, about l.-i feet; from Cedar Point to Long Point, about 
1.5 feet. 

The most important streams in the county are Chaptico Creek, Mcintosh 
Eun, St. Clement, and St. Mary's rivers. In addition to these four 
small rivers, there are many smaller creeks along the coast, all of which 
have the same general characteristics. The basins and beds of the 
streams are flat, with considerable length of tidal flow. No water power 
is now utilized in the county, but at one time a small power on St. 
Mary's Eiver was in use in a flour mill at Clements. 

CHAPTICO CREEK. 

This small stream is formed near the village of Chaptico by the 
junction of two branches, one rising near Charlotte Hall and the other 
near Mechanicsville, and has a total drainage area of 32 square miles. 
Its basin is composed mostly of timber land, with a few farms on the 
higher part. The slopes are gentle and the soil is generally sandy. 
The lower part of the basin is flat, and below the village of Chaptico 



178 THE IIYDKOCHAPIIY OF ST. MARY's COUNTY 

is a niarsli. The effects oi' (inliiuirv tide extend a short distance above 
the highway bridge at C'haptico. The banks of the stream are low and 
subject to overflow during- high water. Tlie velocity of the current is 
generally quite rapid until tide-water is reached. The discharge on 
July 9, 1904, was measured by current meter by E. J. Taylor at a point 
about one-half mile above the highway l^ridge near Chaptico, and found 
to be 12 second feet. 

ST. CLEMENT RIVER. 

St. Clement Eiver has a total drainage area of 23 square miles. Its 
basin has a gentle, even slope and is almost flat in the lower part; on 
the higher part there are several farms, but near the stream the land 
is marshy and is covered with underbrush and timber. Below the high- 
way bridge, at Clements, the basin is one large marsh. The effects of 
ordiiuiry tide extend nearly to this bridge. The velocity of tlie current 
is rajjid in the upper part of the stream, becoming sluggish as it strikes 
tide-water. The discharge on July 11, 1904, was measured by current 
meter by E. J. Taylor and found to be G.6 second feet. 

MCIXTOSn RUN. 

Mcintosh Eun, which has a total drainage area of 26 square miles, 
empties into Breton Bay, near Leonardtown. Its basin is mostly timber 
land, with farms along the tops of the divides. The banks of the stream 
are low, heavily wooded and subject to overflow for almost the entire 
length of the stream. Tlie bed is full of old logs and drift wood. In 
the upper part, the velocity of the current is generally rapid, while in 
the lower part the water stands in long, deep pools, with swift shoals 
between. At the head of Breton Bay, the stream flows into a marsh. 
The discharge on July 11, 1904, was measured by current meter by 
E. J. Taylor at the highway bridge, about one mile above Leonardtown, 
and found to be 4.7 second feet. 



THE MAGNETIC DECLINATION IN 
ST. MARY'S COUNTY 



BY 

L. A. BAUER 



Magnetic observations for the pnrpose of determining the magnetic 
declination of the needle, or the " variation of the compass," have been 
made by the Maryland Geological Survey and the United States Coast 
and Geodetic Survey at the following points within the coimty. 

TABLE I. 
Magnetic Declinatioxs Observed ix St. Mary's County. 



No, 



6 

6A 

6 



Station. 



Lati- 
tude. 



Leonardtown 



Mechanics- 
ville. 



38 17.4 



38 36.6 



Longitudel j^^^^e of 
Gr'nwich. Observation 



V6 38.1 Sep. 12, 1896 



Magnetic 
Declinationon 



Jan. 1, 
1900, west 



Date 
west 



4 43.3! 4 53.1 



June 37, 1900 4 54.6 



76 44.7 'Sep. 11, 1896 



4 43.4' 4 53.3 



Observer. 



Remarks. 



L. A. Bauer 1896 Sta., C.H. 
J. B. Baylor Merid. L.,S.M. 

L. A. Bauer Hotel 

i Mattingly 



All values refer to mean of da.y (24 hours). 

Since January 1, 1900, the value of the magnetic declination has in- 
creased annually by about three minutes (3'), so that on January 1, 1906, 
for example, the north end of a compass would bear at the south monu- 
ment of the Leonardtown meridian line about 5° 11' W., on the average 
for the day. 

DESCRIPTION OF STATIONS. 

Leonardtown. — The 1896 station was in the southwest corner of the 
courthouse but has been superseded by the 1900 station, Avhich is the 
south monument of the meridian line in the courthouse square, 9 feet 
from the wooden fence on the south side, and 9 feet from west wooden 
fence. The north monument is about 300 feet to the north of the south 
monument. 



180 THE MAGNETIC DECLIXATION IX ST. MARY's COUNTY 

Mechanicsville. — In the garden of Hotel ]\Iattingly, 18 feet north- 
east of mulberry tree and 9 J feet west of wooden fence. 

For a description of the methods and instruments used, reference must 
be made to the " First Report upon Magnetic Work in Maryland," (Md. 
Geol. Survey, Vol. I, pt. 5, 1897). This report gives likewise an 
historical account of the phenomena of the compass-needle and discusses 
fully tlie diflBculties encountered by the surveyor on account of the many 
fluctuations to which the compass-needle is subject. Surveyors of the 
county desiring a copy of this report should address the State Geologist. 
In the Second Eeport (Md. Geol. Survey, Vol. V, pt. 1, 1902), the 
various values observed in Maryland have been collected and reduced. 
Surveyors of the county desiring these reports should address the State 
Geologist. 

MERIDIAN LINE. 

On June 27, 1900, Mr. J. B. Baylor, acting under instructions of 
the Superintendent of the United States Coast and Geodetic Survey as 
issued to him, in response to a request from the State Geologist, estab- 
lished a true meridian line at Leonardtown, in the courthouse square. 
This line is marked by two substantial monuments, suitably lettered and 
firmly planted in the ground. (See description above.) 

The South Stone should be the one to be used by surveyors 
when making their tests, if still well removed from all disturb- 
ing influences. 

When the surveyor determines the value of the magnetic declination, 
it would be well for him to make the observations on several days, if 
possible. Probably the best time of day for making the observations 
would be towards evening, about 5 or 6 o'clock.' At this time the declina- 
tion reaches, approximately, its mean value for the day (see Table II). 
The observations on any one day should extend over at least one-half 
of an hour, preferably an hour, and the readings should be taken every 

' Or the surveyor may make his observations in the morning and early in 
the afternoon, at about the time of minimum and maximum values of the 
magnetic declination. He may regard the mean of the two extreme values as 
corresponding closely to the mean value for the day (24 hours). 



MAKYLAXD GEOLOGICAL SURVEY 



181 



ten minutes. Before each reading of the needle it wonhl be well to 
tap' the plate lightly with the finger or a pencil so as to slightly disturb 
the needle from the position of rest it may have assumed. The accurate 
time should be noted opposite each reading and a note entered in the 
record-book as to the date, the weather and the kind of time the observer's 
watch was keeping. It is very essential that the surveyor should have 
some knowledge as to the erro/ of his compass. He can determine this 
by making observations as stated at the South Meridian Stone. He 

TABLE II. 



Month. 



6 

A.M. 



7 


8 


9 


10 


1 
+0.2 


1 
+1.0 


+3.1 


+2.4 


+0.7 


+1.5 


+1.9 


+1.4 


+3.0 


+3.0 


+3.8 


+ 1.6 


+8.1 


+3.4 


+3.6 


+ 0.8 


+3.8 


+3.9 


+3.6 


+0.1 


+ 4.4 


+4.4 


+3.3 


+ 1.1 


+4.fi 


+4.9 


+3.9 


+ 1.8 


+ 4.9 


+ .5.4 


+3.7 


+0.4 


+3.8 


+3.4 


+3.6 


+0.3 


+ 1.6 


+3.1 


+3.8 


+1.4 


+ 1.3 


+ 1.7 


+ 1.8 


+1.1 


+0.3 


+0.8 


+1.8 


+1.8 



1 


'2 


3 


/ 
-2.5 


1 
-2.6 


-2.1 


-2.1 


-3.5 


-2.0 


-3.4 


-3.7 


-3.3 


-4.1 


-4.2 


-3.6 


-5.0 


-4.5 


-3.6 


-4.5 


-4.5 


-3.8 


-4.4 


-4.7 


-4.2 


-5.1 


-4.9 


-3.7 


-4.6 


-4.3 


-4.0 


-3.3 


-3.4 


-2.4 


-3.7 


-2.6 


-1.8 


-2.4 


-3.3 


-1.8 



January —0.1 

February +0.6 

March +1.2 

April +3.5 

May +3.0 

June +3.9 

July +3.1 

August +3.9 

September... j+1.8 

October +0.5 

November +0.5 

December +0.3 



+1.3 
-0.1 
-0.6 
.1 
.4 
-3.0 
-1.3 
-3.8 



1.1 
-1.5 
-3.5 
-4.0 
-4.0 
-3.6 
-3.4 
-4.7 



-1.3 
-1.3 
-2.3 
-2.3 
-2.3 
-3.6 



-3.7 -4.4 



-1.0 
-0.5 
-0.0 



-3.7 
-2.0 
-1.6 



-0.3 
-0.8 
-1.3 
-1.3 
-0.9 
-1.3 

3.8 -1.3 

1.9 -0.6 
1.4 -0.3 
1.3 '-0.4 

1.0 -0.3 

1.1 -0.3 



+0.3 
-0.4 
-0.5 
-0.3 
+0.1 
-0.3 
-0.3 
+0.3, 
-0.1 
-0.4 
+0.3 
+0.1 



should reduce the value of 4° 53' to the date of his tests^ by allowing an 
annual increase since January 1, 1900, as above stated, of 3', and the 
difference between this value and his own will be his compass error. 

If the surveyor has an instrument which admits of the refinement to 
take into account the change in the magnetic declination during the day, 
he may use the above table to correct his readings. 

To reduce an observation of the magnetic declination to the mean 
value for the day of 24 hours, apply the quantities given in the table 
above with the sign as affixed. 



^ Great care must be taken not to electrify the needle by rubbing the glass 
plate in any manner. Remarkable deflections of the needle can thus be 
produced. 

^I have found surveyors' compasses to differ at times as much as 1° from 
the readings with the Coast and Geodetic Survey Standard Magnetometer. 
The error may be due to a variety of causes, such as an imperfect pivot, non- 
coincidence of magnetic axis of needle with the geometric axis, loss of mag- 
netism of the needle, or impurity of brass of which the compass box is con- 
structed. 



182 



THE MAGNETIC DECLINATION IN ST. MARYS COUNTY 



This table shows that dm-ini-- August, for exaiupk^, the magnetic de- 
clination has its lowest \a\uv ahont S a. m. and its highest value at about 
1 p. :\i., and that between these two liours the needle changes its direction 
about 10', which amounts to 15 feet per mile, in wiiilcr (lie change is 
considerably less. 

Table III shows how the magnetic ileclination has clianged at Leonard- 
town between 1700 and lijor). 

From this table it will be noticed that the needle is at tlic present time 
pointing about the same amomit to the west that it did two centuries 

TABLE III. 



Year 


Needle 


Year 


Needle 


Year 


Needle 


Year 


Needle 


Jan. 1. 


pointed. 


Jan. 1. 


pointed. 


Jan. 1. 


pointed. 


Jan. 1. 


pointed. 


1700 


50 07' W 


1750 


30 23' W 


1800 


0° 26' W 


1850 


P 56' W 


10 


4 46 


fiO 


1 48 


10 


25 


60 


2 &3 


20 


4 16 


70 


1 15 


20 


35 


70 


3 12 


90 


8 40 


80 


r,o 


30 


6fi 


80 


3 49 


40 


3 01 


90 


3:} 


40 


1 ,•23 


90 


4 23 


60 


2 23 W 


1800 


:.'»■) w 


50 


1 or, w 


1900 
1905 


4 53 

5 08 W 



ago, and that in about 1805-10 the magnetic declination had its lowest 
value of about 25' west, after which it began to increase again. In al)Out 
a century, since 1805, the compass has, accordingly, changed its direction 
about 4f °. 

A street a mile long, laid out in LeonarcUown in 1805 to run north and 
south by the compass, would, at the present time (1905), have its north 
terminus about 1/12 of a mile too far east! 

The above tal)le enables the surveyor to ascertain the precise amount 
of change in the magnetic declination oi- pointing of the compass between 
any two dates between 1700 and 1900. It should be emphasized, how- 
ever, that when applying the quantities thus found in the re-running of 
old lines, the surve^^or should not forget that the tabic cannot attempt 
to give the correction to l)e aliowiMl on accoimt of the eri'or of the com- 
pass used ill tlic original survey. 



THE FORESTS OF ST. MARY'S COUNTY 

BY 
C. D. MELL 

Introductoey. 

The forested areas of St. Mary's Coimty are evenly distributed through- 
out, as shown by the accomijanying map. As a rule, timber is left 
standing along the streams and al)out swamps, and occasionally along 
the bay shores. The slopes near the banks of streams are seldom 
cleared, owing to the danger of their becoming gullied and otherwise 
eroded. This precaution gives considerable area under forest cover. 
On the higher reaches, and on the well-drained and sandy portions form- 
erly cleared for farming purposes and later abandoned, the areas have 
grown up to scrub pine. Where the soil was not too poor, hardwood 
species, principally red gum, oaks, and hickory, have formed a mixed 
stand with the scrub pine. Loblolly pine takes the place of scrub pine 
in moister situations. There are 105,900 acres of forests, while 13-i,i40 
is farming land. The more fertile farming land lies along the Potomac 
and Patuxent rivers. 

According to the testimony- of the old inhabitants, the forests of this 
part of Maryland Avere originally composed chiefly of hardwood species. 
They claim also that when their fathers Avere boys there was hardly a pine 
to be seen, but that by the gradual clearing away of the original forest, 
and by the exhaustion of the soil, it could no longer yield a good crop 
of the exacting hardwoods. In consequence, the less exacting pine has 
come to form a considerable part of the forests of the county. Areas 
which are said to have been forinerly covered with very desirable species 
of oaks, chestnut, poplar, and red gum are now covered A\-ith scrub pine 
and lol)lolly pine. The scrub pine came in from the north and the 



184 THE 1UKESTJ5 or ST, mauy's county 

loblolly from the south. This is evident from the fact that the scrub 
pine is very abundant in the northern part of the county, and decreases 
toward the southern part; wliile the loblolly pine is growing in pure 
stands in the southern part, becoming less abundant toward the north. 

There Avere no treeless areas in the county, except those under culti- 
vation, and small areas along the coast where brackish water comes in 
and renders the soil unfit for tree growth. These areas are usually 
covered with a dense mat of grasses and sedges. 

The character of the present forests and their condition bears no re- 
semblance to the original forests. The original forests have suffered 
so much from unconservative cutting that to-day only the less important 
timber species are represented on large areas. The post and black-jack 
oaks, sour gum, persimmon, chinquapin, birch, and scattered elm, beech, 
and ashes are the most frequent species. There is only a small amount 
of 3'ellow poplar immediately bordering the streams. The pines are of 
small size and the hardwood forests are so mixed with small, uneven- 
aged trees that they cannot }ield more than a home supply of lumber. 
The frequent extensive opening of the forest has resulted in dense growths 
of brush which rendered it almost impossible for the more important 
tree species to come in. 

Character axd Composition. 

The forests of St. Mary's County are peculiar in being made up of 
trees very variable in age, kinds, and species. The occurrence of species 
changed markedly with the condition of the soil in different localities. 
Along the river bottoms where the soil is moist and gravelly the red 
gum, black ash, yellow poplar, and willow oak thrive most abundantly. 
In a zone just above this, where the soil is of sand and clay and well- 
drained, the white, red, scarlet, yellow, and Spanish oaks mingle with 
scrub pine, chestnut, hickory, and birch. Still farther up on tlie higher 
reaches the rock oak and chestnut predominate. Here the soil is sandy 
and well-di'aini'il, and scrub pine is rai)idly taking the ])laco of hard- 
woods. 

The soil is sufficiently fertile to support a vigorous growth of all the 



MARYLAND GEOLOGICAL SURVEY, 



ST. MARY'S COUNTY, PLATE XIII. 




4 



Fig. I. — VIEW showing mixed forest growth on a clay soil. 




Fig 



. 2. — VIEW SHOWING THE HEAD OF A TIDAL RIVER. 



MARYLAND GEOLOGICAL SURVEY 185 

species just mentioned. Trees of all sizes are represented, from one-year- 
old seedlings to mature specimens of the original forest. In the bottom 
lands, the reproduction is very good, consisting chiefly of red gum, elm, 
and ash. On the better-drained areas, the young growth consists largely 
of sprouts of chestnut, oak, hickory, and maple. The frequent opening 
of the forests affords plenty of light for undesirable tree species to come 
in, such as the dogwood, black gum, mountain laurel, persimmon, chin- 
quapin, and blue beech. These unimportant species, in addition to the 
scrub pine on well-drained areas, form 60 per cent of the stand, and in 
some jjlaces the proportion is even greater. 

The climatic position of St. Mary's County is so favorable that it 
exhibits floral features similar to those of the adjacent Southern States. 
On this neck, loblolly pine finds its northern limitation. The following 
is a complete list of the trees native to St. Mary's County : 

Conifers. 

Coinmon Name. Botanical Name. 

1. Pitch Pine Pinus regicla Mill. 

2. Scrub Pine Pinus virginiana Mill. 

3. Loblolly Pine Pinus twcla Linne. 

4. Red Juniper Juniperus virginiana Linne. 

Hardwoods. 
Common Name. Botanical Name. 

5. Butternut Juglans cinerea Linne. 

6. Black Walnut Juglans nigra Linne. 

7. Butternut Hickory Hicoria minima (Marsh) Britton. 

8. Mockernut Hickory Hicoria alba (Linne) Britton. 

9. Pignut Hickory Hicoria glabra (Mill) Britton. 

10. White Willow Salix alba Linne. 

11. Largetooth Aspen Populus grandiclentata Michx. 

12. River Birch Betiila nigra Linne. 

13. Sweet Birch Betula lenta Linne. 

14. Blue Beech Carpinus caroliniana Walt. 

15. Beech Fagus atropunicea (Marsh) Sudw. 

16. Chestnut Castanea dentata (Marsh) Borkh. 

17. Chinquapin Castanea pumila (Linne) Mill. 

18. White Oak Quercus alba Linne. 

19. Post Oak Quercus minor (Marsh) Sargent. 

20. Chestnut Oak Quercus prinus Linne. 

13 



1S(J Till-: FORESTS OF ST. MAKY's COIXTY 

21. Swamp White Oak Qucrcus plataiioides (Lam) Sudw. 

22. Cow Oak Quercus michauxii Nutt. 

23. Red Oak Quercus rubra Linn6. 

24. Scarlet Oak Quercus coccinea Muenchh. 

25. Yellow Oak Quercus velutina Lam. 

26. Spanish Oak Quercus digitata (Marsh) Sudw. 

27. Pin Oak Quercus palustris Muenchh. 

28. Black Jack Oak Quercus viarilandica Muenchh. 

29. Willow Oak Quercus phellos Linn6. 

30. Slippery Elm Ulmus pubescens Walt. 

31. White Elm Ulmus americana Linn6. 

32. Hackberry Celtis occidentalis Linn6. 

33. Red Mulberry Morus rubra Linne. 

34. Sweet ^Magnolia Magnolia glauca Linne. 

35. Yellow Poplar Liriodendron tulipifcra Linne. 

30. Papaw Asimina triloba (Linne) Dunal. 

37. Sassafras Sassafras sassafras (Linne) Karst. 

38. W'itch Hazel Harnamelis virginiana Linne. 

39. Red Gum Liquidambar styraciflua Linn6. 

40. Sycamore Platanus occidentalis Linne. 

41. Service-berry Amelancliier canadensis (Linne) 

Medic. 

42. Scarlet Haw Cratagus coccinea Linne. 

43. Black Cherry Prunus serotina Ehrh. 

44. Red-bud Cercis canadensis Linne. 

45. Honey Locust Gleditsia triacanthos Linn6. 

46. Locust Kobinia Pseudacacia Linne. 

47. Staghorn Sumach Rhus hirta (Linng) Sudw. 

48. Dwarf Sumach Rhus copallina Linne. 

49. Holly Ilex opaca Ait. 

50. Silver Maple Acer saccharinum Linne. 

51. Red Maple Acer rubrum Linne. 

52. Boxelder Acer negundo Linne. 

53. Basswood Tilia americana Linn6. 

54. Flowering Dogwood Cornus florida Linn6. 

55. Black Gum Xyssa sylvatica Marsh. 

56. Mountain Laurel Kalmia latifolia Linne. 

57. Great Rhododendron Rliododendrum maximum Linne. 

58. Persimmon Diospyros virginiana Linne. 

59. Black Ash Fraxi7ius nigra Marsh. 

60. White Ash Fraxinus americana Linn6. 

61. Red Ash Fraxinus pennsylvanica Marsh. 

62. Nannyberry Viburnum prunifolium Linn6. 

There are a considerable number of exotic trees growing in this 
region which were introduced here by the early settlers who planted 



MARYLAXD GEOLOGICAL SURVEY 187 

them in yards and along roads and lanes. A few of these species have 
escaped from cultivation and are found mixed with the native trees 
along the borders of wood lots. The most important ones are : 

Common Name. Botanical Name. 

Norway Spruce Picea excelsa Link. 

Silver Fir AMes j^ectinata D. C. 

Englisii Walnut Juglans regia Linne. 

European Hornbeam Carpinus hetulus Linne. 

Weeping Willow Salix babylonica Linne. 

Paper Mulberry Broussonetia papyrifera (Linne) 

Vent. 

Tree-of-Heaven AilantMis glandulosa Desf. 

Paulownia Paulownia tomentosa (Thunb.) Steu- 

del. 
Catalpa Catalpa kwvipferi Seib. and Zucc. 

Types of Forest. 
The forests of St. Mary's County are conveniently divided into three 
types: (a) Mixed hardwoods, (])) mixed hardwoods and pine, (c) 
pure pine. 

(a) The mixed hardwoods cover the largest percentage of forested land 
in this county, and invariably occupy the rich, gravelly soil along the 
water courses. The predominating species of this type are red gum, 
yellow poplar, black ash, sycamore, oaks, beech, and white elm. The 
most valuable timber is now being cut from this type, while several species 
are continually culled out for special purposes. Through this cutting 
the mixed hardwood type has greatly diminished in value. The best 
and also immature trees are removed, while the over-mature and forest 
tree weeds are left to grow and prevent the best species, such as the 
yellow poplar, ash, and red gum, from reproducing. 

(b) The mixed hardwood and pine type occupies the area immediately 
bordering the mixed hardwood type. The principal trees represented are 
the red and white oaks, sour gum, scrub pine, and a small amount of 
loblolly pine. This type covers the well-drained areas which have never 
been cleared for agricultural purposes. This forest is more or less open, 
and shows a tendency to predominate, especially on the borders of open 
fields and roads. 



ISS THE FORESTS OF ST. MARY'S COUNTY 

(c) The pure pine type is found invariably on tlie higher situations 
and on hmd which lias been cleared for farming purposes. In the cen- 
tral and iinrlhern part of the county, these pure pine forests consist 
mainly of scrub pine with a mixture of some loblolly in moist situations, 
while near the Bay shore and in the southern part of the county the 
loblolly pine occurs in pure stands in old fields and on cut-over land. 

Valuable Commercial Trees. 

Bed Gum. — This species is confined chiefly to moist situations along 
streams and ponds. It is associated with yellow poplar, willow oak, 
black ash, beech, and oaks. The less important associates are iron- 
wood, sour gum, chestnut, and loblolly pine. In a few places it forms 
pure stands of an acre or more. 

Eed gum is sought largely for veneer and fruit baskets. Several 
mills in St. Mary's County have been cutting red gum exclusively for 
some time. The bulk of red gum timber has, however, been harvested, 
and the demand is such that the timber is cut at a diameter of 8 inches 
on the stump. 

In the meadows or in open places in the forest, where the underbrush 
is sparse or lacking, seedlings of red gum come up in pure stands. It 
requires abundant light in early youth, and considerable soil moisture, 
but with the necessary light and moisture it thrives equally well on sandy 
loam or clay. 

Yellow Poplar. — The general soil and moisture requirements of the 
yellow poplar are very similar to those of red gum, with which it is 
commonly associated. This species was the first to be cut for building 
purposes, and at the present time there is very little mature yellow 
poplar remaining. The demand for this wood for paper pulp is con- 
stantly increasing. Along the streams there is some reproduction, but 
the less important species crowd it out. The young seedlings cannot en- 
dure shade, and, therefore, cannot grow up in locations where the ground 
is covered with a dense growth of weed trees. Sprouts grow from the 
stump but they very seldom become trees. Seeds are produced every 
year, but only a small percentage of them are fertile. Young trees 



MARYLAND GEOLOGICAL SURVEY. 



ST. MARY'S COUNTY, PLATE XIV. 




;U^ 











Fk;. 1. — \IE\\ .SHOWING RED GUM GROWTH ALONG STREAMS. 




Fig. 2. — VIEW showing reproduction of red gum. 



MARYLAND GEOLOGICAL SURVEY 189 

very rarely produce any good seed at all, and the older trees are being 
so rapidly removed from the forest that reproduction, is hopeless. 

White Oak. — This species occurs along the well-drained banks of 
streams and in alluvial soil generally. Originally, it occupied consider- 
able areas of what is now agricultural land, and was largely associated 
with the red and black oaks, which are similar in their requirements of 
soil and moisture. There is considerable white oak scattered throughout 
the county, but owing to poor transportation facilities, it has a rather 
low stumpage value. The market demand for white oak ties and for 
bridge timber is steadily increasing, since the red and black are no 
longer accepted in this section by the principal railroads. The white 
and other oaks are used more generally for fuel in this county than 
any other timber, and command the highest prices for this purpose. A 
good deal of white oak dimension stuff is used locally. Some piles are 
cut and shipped out of the county. 

The white oak is being rapidly replaced by less valuable timber trees, 
such as black jack and post oaks, persimmon, black gum, and scrub pine. 
Eeproduction by both seed and sprouts requires considerable sunlight, 
which is often impossible under the unsystematic selective method of 
cutting now generally practiced. The older trees bear some seed every 
year, but very few are left to spring up. Eodents of the forest are very 
fond of the sweet meat of the white oak acorn, and so are the swine 
which are left to run through the woods the greater part of the year. 

Chestnut. — The chestnut is peculiar to the higher, drier, and well- 
drained slopes. Formerly this species was much more abundant than 
it is now, at present being represented by old, and, frequently, over- 
mature trees scattered through the forest. There is little tendency to 
reproduce itself from seed, and the trees that are cut are frequently 
too old to sprout well from the stump. In consequence, there is very 
little chestnut left in the county. It is largely replaced by rock, post, 
and black-jack oaks, scrub pine, and black gum. The dealers are eager 
to buy the chestnut, and unless measures are adopted to extend and 
maintain the growth within a few years, very little of this timber will be 
available. Woodlot owners cut their chestnut for fencing material before 



li)0 THE FORESTS OF ST. MAKY'S COUNTY 

any other species except red juniper. It is also frequently sawn into 
staves for tobacco hogsheads. A few sawmills convert chestnut timber 
into shingles. It is also used to some extent for fuel, but brings a 
lower price than oak. There is very litle of this timber remaining in 
the forest suitable for telephone and telegraph poles, for which it was 
formerly very largely used, and for which there is a good demand. 

LohloUy Pine. — In St. Mary's County, loblolly pine is most abundant 
on the sandy clay soil near the Bay shores, though it occurs frequently 
in the interior and on elevated slopes, mixed in with scrulj pine and 
hardwoods. It appears to be rather tolerant of shade in this range, 
seldom coming up in the dense forest. In old fields, however, where 
there is no competition with other species, it does form dense stands. 
Tlie best examples of pure growth are found in the southern part of 
the county near Point Lookout. Here it forms long, clear boles with 
small crowns, and is eagerly sought for piles, telephone and telegraph 
poles. 

Eeproduction is very good in all locations with suitable soil and suffi- 
cient light. Loblolly pine })roduces seed every year. Cones mature 
the second year and slowly discharge their seed during the autumn 
and winter, and usually remain on the branches until the end of another 
year. Open places in the forest where conditions are not too unfavorable 
are seeded up in the course of two or three years. The scrub pine is 
more prolific in its production of seed, and is more tolerant of sluide tlian 
the loblolly pine, but the latter grows faster in its early youtli and 
soon overtops the scrub pine. From the good reproduction of loblolly 
pine in southern St. Mary's County and that of scrub pine in the central 
and nortliern part, it is evident that these two species will furnish the 
bulk of the future timber sup])ly. 

Scrub Pine. — The scrub pine is less exacting than loblolly pine in 
its requirements of soil and moisture. It generally occurs unmixed 
with other species in old fields and in other open places. Until recently, 
this pine had no speeial use except foi' firewood, and was considered 
a weed. Now, however, the wood is used for various purposes, the most 
important one being for the manufacture of paper pulp. Large cpian- 



MARYLAND GEOLOGICAL SURVEY 191 

titles are aminally shipped out of the count}' for this purpose. There 
are minor uses to which this wood is put, and other uses are sure to 
follow. It is largely used for fuel though none is shipped out of the 
county for this purpose. Considerahle scrub pine timber is being cut 
and sawn into lumber for house construction locally, and practically all 
lumber used for tobacco hogshead staves is from this pine. Boards for 
fencing are largely cut from scrub pine. It is the principal timber 
used in locations where it comes constantly in contact with water, as in 
flumes for conducting water to mill-wheels and in irrigation ditches. 

The scrub pine is a very prolific seed producer. It requires two years 
for the cones to mature, and the trees, having plenty of light, are gen- 
erally loaded with cones which remain on the branches for three or 
four years after maturity. Seeds are shed rather slowly, and, being 
small, are easily wafted by the wind for considerable distances. Old 
fields bordering a growth of scrub pine come up to this species, within 
a few years. It forms a very dense stand, and, being tolerant of shade, 
it does not prune itself of its lower branches until it is twenty or twenty- 
five years old. At the age of forty or fifty years the stand becomes more 
open, and mixed with hardwoods. 

In locations where clear cutting is made and scrub pine is desired 
for a second growth it is necessary to leave from 3 to 5 seed trees to an 
acre. 

Red Juniper. — The red juniper is common in all localities and soils 
in this county. It comes up in old fields where other reproduction is 
tardy, and is especially conspicuous as a roadside tree throughout this 
region. Long and regular rows have come up along roads and lanes 
from seed dropped by birds. The scarcity of chestnut brings this species 
into greater favor for fence posts and when the trees have attained a 
diameter of 4 or 5 inches breast-high, farmers generally prune them of 
their lower branches. Cedar posts sell with local dealers for about 
$20.00 per hundred. 

The red Juniper thrives best in sandy and loamy, moderately moist 
soil, but this county grows it in rather dry, sandy clay and gravelly soil. 
It prefers sunny, open situations. In the forest this species remains 



192 THE FORESTS OF ST. MARY's COLXTY 

small and stuuted, but in open places it forms a long conical crown. It 
produces seed in abundance, but the percentage of germination is very 
low. 

Transportation. 

The lack of good transportation facilities in central and southern 
St. ]\Iary's County has had considerable to do with regard to the amount 
of timber made available. There is very little timber being shipped 
into the county, and statistics gathered from the sawmills show that 
less than 2,000,000 board feet are shipped out annually. The bulk of 
the wood shipped goes out by boat and tlio remainder by rail. The 
Washington & Potomac IJailroad runs into the county only a short dis- 
tance from the north, with its terminus at Mechanicsville, and is con- 
nected with the Pennsylvania line at Brandy wine, Maryland. Tliis 
affords very little opportunity for the shipment of forest products by 
rail, unless shipments are hauled over sandy roads for long distances. 
Such hauling is so expensive that it does not pay to cut all the useful 
trees in a forest. Therefore, only the best of certain species, such as 
will warrant the expense of shipment, are cut. The remainder is left 
in the forest to rot or to hinder other desirable species from springing 
up. Accordingly, the owners of forest land in some sections of the 
county appear to have failed to realize the fullest production from 
their timber, and are willing to sell it regardless of the result it will 
have on their forests. 

As a rule the wagon-roads in the county are not suitable for hauling 
very heavy loads. For the most part they are exceedingly sandy, and 
where grades occur they are gullied and so narrow at many points that 
they are almost impassable. 

Present Wood CoNsuMrTiox. 

The principal uses for wood are considered under the following head- 
ings: 

Sawmills and their products, cordwood, railway ties, pulpwood, veneers, 
telegraph poles and piles, fence timber and staves. 



MARYLAND GEOLOGICAL SURVEY. 



ST. MARY'S COUNTY, PLATE XV. 



" ■ -f • 









h 



MAKTLAXD GEOLOGICAL SURVEY 193 

Sawmills and their Products. — There are about twenty-two saw- 
mills cutting timber in St. Mary's County. The amount cut by each 
mill ranges from 25,000 to 1,500,000 board feet annually. These mills 
are scattered throughout the county, and have a combined annual cut 
of 7,075,000 board feet. The bulk of the timber cut in these mills is 
pine, oaks, yellow poplar, and red gum. Of these only the best grades 
are shipped out of the county. 

In the southern part of the county about two-thirds of the timber cut 
is pine and one-third hardwood, while in the northern part this propor- 
tion is about one-third of pine to two-thirds of hardwood. On an 
average for the whole county, about one-half is pine and one-half hard- 
woods. A good deal of the best grades of pine and white oaks are sa^vij 
into construction timber and shipped out of the county, while the 
remainder is cut into boards, planks, and dimension stuffs for local use. 
Occasionally red gum is sawn for outside shipments, but until recently 
the market price of this timber has been so low that the mill men could 
not cut it profitably. Eed gum is now bought largely for the manu- 
facture of fruit baskets. It is also used locally for construction timber 
and for such less important purposes as staves for tobacco hogsheads, 
boards for fencing, and for shingles. 

Of the entire amount of timber cut into lumber, only about 1,500,000 
board feet are shipped out of the county. This leaves approximately 
6,000,000 board feet for local consumption. With a joopulation of nearly 
16,000, this allows a consumption of 370 board feet per capita. The 
average consumption per capita in the United States is being placed at 
510 ' board feet. 

CORDWOOD. — The supply of firewood in St. Mary's County is a simple 
problem. Firewood is abimdant and the cost per cord on the market 
is determined largely by the cost of cutting and hauling. The best 
quality of hardwood can be bouglit on the stump for less than 50 cents 
per cord in almost any locality, while scrub pine sells for 35 cents or 
less. It is estimated that approximately 2000 cords of firewood are 

^Forest Economics, B. E. Fernow. 



194 THE FORESTS OF ST. MARY's COUNTY 

shipped out of the county every year. It goes jji'iiicipiilly to Ualtiniore 
and Washington. Hardwood brings $'^.50 per loi'd at the wliarf, and 
pine $2.00. 

From the data gathered within llx' county it is estimated that the 
4000 families in St. Mary's County use approximately 55,000 cords 
of wood annually, or an average of 14 cords per year for each family. 
Eleven cords can be cut on an average from an acre of forest land, so 
that the annual consunijjtion of firewood in the county represents a 
stand of timber of about 5200 acres. On the 105,900 acres of forested 
land there is now standing approximately 1,1G5,560 cords of wood, 
counting 11 cords to an acre. This includes all standing timber over 
4 inches in diameter on the stumjx At the present rate of consinnption 
it would require aijout twenty-one years for all the wood to be consumed 
in the county in the form of cordwood alone, not counting the annual 
increment of the forest in the meantime. The volume of this yearly 
increment of the forest is estimated to about l)alance the total consump- 
tion, though the kiml and quality of the timber is constantly deteriorating 
under the present lack of proper conservative management. 

Eatlway Ties. — The forests of St. Mary's County have long been an 
important source for ties and other railroad construction timber. The 
supply for these purposes is now, however, almost exhausted. Formerly 
several hundred tliousand ties were cut and shipped annually, Init during 
the last two years the shijjments were less than 50,000 tics and hardly 
any bridge timber. Up to the last year (1904) the railroad companies 
accepted all kinds of oak and chestnut ties produced by the county, but 
at the present time (1905) they desire only white oak and chestnut. 
'J'his will materially diminish the future cut of ties in the county. 
Moreover, owners of timber are somewhat reluctant to sell white oak 
to contractors who will not at the same time accept red and black oak 
timber. 

The Spanish, red, yellow, and otlier Idack oaks are considered inferior 
grades by railroad companies, and experience has proved to Ihcin tliat 
the life of a tie cut from one of these oaks is only a little more than 
half that of a white oak tic Contractors realize from GO to 70 cents 



MARYLAND GEOLOGICAL SURVEY 



195 



for their white oak ties, depending npon the grade of tie. Chestnut ties 
range from 45 to 55 cents, delivered at the railroad. Two classes or 
grades of ties are distinguished hy contractors and railroad companies. 
The first class includes ties whidi have a face of 8 inches or over and 
are free from all defects, such as knots and checks. Second class ties 
may have some knots and a. face of not less than T inches. All oak ties 
must he hewn. Chestnut ties are cut largely from old mature trees, 
and are cut into their required dimensions in the sawmill. 

Contractors hire choppers who cut ties at the rate of 10 cents for 
the hest grade and 8 cents for the second grade. 

PuLPWOOD. — Yellow poplar and scruh pine are cut extensively for the 
manufacture of wood pulp. The latter is used in excess of the former 
solely hecause it is more abundant in the county. Experienced dealers 
in the county estimate tliat about four thousand cords of pulpwood are 
shipped annually out of the county. About one-fifth of this amount is 
yellow poplar. 

Scrub pine, being much more abundant, is the staple timber for this 
purpose, and consumers of pulpwood have no difficulty in Iniying large 
tracts of it at very low prices. Stumpage prices of pine vary according 
to the distance from railroad or wharf, and also according to the age 
and density of stand. The different items making up the price per cord 
of scrub pine for pulpwood vary as follows: 

Stumpage ? -20 to $ .25 

Cutting 1-25 " 1-40 

Hauling 1-30 " 1-50 



Total 



f2.75 " $3.15 



The scrub pine is cut during the spring and summer seasons when 
the bark can be taken off most easily. All trees above 4 inches in 
diameter a foot above the ground are cut into 5-foot lengths. A saw is 
used so as to insure uniform lengths and facilitates in loading on cars 
or boats. Scriib pine has only lately come into favor for pulpwood, and 
it is believed that the demand for this species will increase. Loblolly 
pine is not cut for pulpwood. 



196 THE FORESTS OF ST. MARY's COUNTY 

Owing to the scarcity of yellow poplar it is difficult to secure tracts 
from which this timber can be cut profitably. On an average, 2 cords 
may be expected from one acre of land wlicre the soil is suitable for 
this species. Tracts yielding less than this are seldom worked for pulp- 
wood because of the inconvenience of getting it out of the forest. 
Stumpage prices are usually high, and the trees are so widely scattered 
that it hardly pays to cut them. The following items show the first 
cost of a cord of yellow ])oplar pulpwood : 

Stumpage $ .90 to $1.10 

Cutting 1.40 " 1.60 

Hauling 1.40 " 1.60 

Total $3.70 " $4.30 

Contractors' prices to consumers are generally from $4.50 to $4.75 
per cord, delivered at the landing. 

Vexeers. — The manufacture of red gum veneer for fruit baskets 
is constantly increasing, and the supplying of timber for this purpose 
has become a staple industry in St. Mary's County. Red gum timber 
can be bought from owners for 50 cents per cord on the stump. The 
cost of cutting and hauling is the same as that of yellow poplar, making 
the total cost for one cord of red gum at the wharf about $3.50. The 
market price is about $4.00 per cord containing 173.33 cubic feet. Sticks 
are cut 5 feet long with the bark removed. The cord measures 8 feet 
long and 5 feet wide, by 4 feet and 4 inches in height. 

Telegraph Poles and Piles. — The available timber in tliis county 
desirable for piles, telegraph and telephone poles is white oak, chestnut, 
and loblolly pine. The demand and consumption of chestnut and 
white oak ties has "been so great, however, that very few poles and piles 
have been cut from these species. Contractors for supplies of pole and 
pile timber from this county are, therefore, largely restricted to loblolly 
pine. Formerly, this pine could be bought rather cheaply in the southern 
part of the county, but of late the price, owing to the demand for other 
purposes, or for lumber, has increased so enormously as to prohibit the 
purchase of this timber for piles and poles. Large areas of old fields 



MARYLAND GEOLOGICAL SURVEY 19'^ 

which have come up to loblolly pine are now furnishing material more 
valuable for lumber than any other purpose. 

It is believed that red, yellow, and l^lack oak will find a place on the 
market for piles, since they are no longer accepted for railroad ties, 
especially if preservative treatment is resorted to. These oaks are never 
used for poles, but are constantly used locally for piling in the con- 
struction of private wharfs. 

Fence Timber and Staves.— Eed juniper is the principal species 
used for fence posts, and is noted for its lasting qualities in contact with 
the soil. Sawmill men handle these posts at $20 per hundred, though 
none are shipped out of the county. Boards for fence material are 
largely cut from scrub and loblolly pines, and are quoted on the local 
markets at $11 per thousand board feet. Clapboards are cut from red 
gum, red oak, scrub pine, and loblolly pine. 

Formerly a large number of fence rails and posts were cut from 
chestnut, but since this timber is becoming rather scarce in this county 
farmers resort to red and black oaks, scrub pine, and loblolly pine. 

Staves for tobacco hogsheads are cut largely from scrub pine. Occa- 
sionally loblolly pine and red gum are used. These staves are sold by 
all sawmill men in the county and are 5 feet 4 inches long, and from 3 
to 6 inches wide. They are quoted on the market at $8 per thousand 
board feet. 

Destructive Influences. 
Forest Fires.— The forests of this county have been remarkably free 
from destructive fires. There is no record of a fire having occurred 
within the county which caused any severe damage to the forests. The 
numerous streams of the county serve as natural firebreaks, being nearly 
at right angles to the prevailing winds. These streams are usually bor- 
dered by wet or damp soil and dense vegetation, which is scarcely ever 
in condition to burn readily, and furnish impassable barriers to any 
ordinary fire. The county is also so thoroughly cut up by areas cleared 
for farm purposes that they, with the numerous wagon-roads throughout 



198 THE FORESTS OF ST. MARY's COUNTY 

the county, serve as additional iire-lines. Even the little-used wagon- 
roads are usually gullied by erosion ami devoid of vegetation. 

On the other hand, the people ol' the county are notably very cautious 
in regard to fires, and as there are no very large tracts of forests not 
immediately under the care of the owner himself, or someone directly 
responsible, fires are not left to run on until they cannot be easily put out. 
The immediate danger to which numerous small dwellings or cabins 
scattered throughout the forests are subjected likewise tends to make 
the inhabitants careful regarding forest fires. The prevailing forest 
types, being oi mixed hardwoods, are not especially subject to destructive 
fires since the forest floor is Uf^ually moist and in places even wet. On 
the higher ek'vations where the scrub pine predominates, and on the 
lower level sandy parts, where the loblolly is found, the soil is covered 
with a thin layer of needles which is not sufficient to feed a destructive 
fire. 

The danger of fire from locomotives is very small, since there are less 
than ten miles of steam railw^ay in St. Mary's County. Charcoal burning, 
which is a fruitful source of fires in neighboring counties, is not carried 
on here, and as this county is almost surrounded by water the liability 
of fii'o entering from adjoining localities is practically eliminated. 

Grazing. — This county is not well adapted to grazing. There is not 
enough of it carried on to damage forest reproduction. On account of 
insufficient fodder supply for winter use, very few cattle are kept by the 
farmers. Along the streams and wet places the growth consists of 
shrubs and trees, with very little grass, wliile on the cleared farming land 
the soil is so loose and sandy that cattle would soon trample the meadow 
grass into the sand and ruin the pasture. 

A greater source of damage to the forests of St. Mary's County is 
that afforded by herds of swine which feed in the forest. During the fall 
and early part of the winter, they subsist on mast, but in spring and 
summer they dig up the forest soil in search of roots. The young 
growths are killed and the mature trees are seriously injured. Fre- 
quently, even large trees are killed outright. In their search for the 
soft inner bark of the oaks, chestnut, and pine, hogs remove the bark of 



MARYLAXD GEOLOGICAL SURVEY 199 

the lower part of the trmiks as well as that of the roots, so far as they 
are able to dig them up. 

Other Destructive Influences. — The following are also destructive 
to the forests of this region: injudicious cutting; clearing land better 
suited for forest growth ; and erosion. 

Injudicious cutting of the timber has been going on in this county 
since its settlement. Nearly all of the areas have been cut over many 
times for the purpose of securing certain timber species for special pur- 
poses. This constant stripping the forest of its most valuable timber 
has left not only too few and poor, immature trees as the only repre- 
sentatives of the more valuable species, but it has also permitted the 
less valuable species to become too abimdant. As a direct consequence 
large tracts of forests now present a very irregular and uneven-aged 
appearance, with very few good timber trees remaining. The woodland 
owners of St. Mary's County do not fully realize the decline of their 
forest resources. When wood is needed but little discretion is exercised 
in the choice of trees to be cut, and no provision is made for the renewal 
or improvement of the stand. 

Large areas throughout the sandy and rather unproductive regions of 
the county were stripped of their timber, and cultivated for farm crops 
for several years. When they ceased to yield a crop sufficient to pay 
for the tilling of the soil, they were abandoned and allowed to revert 
to nature. A scrubby growth of oaks, black gums, persimmon, and 
scrub pine now occupies these old farms. Frequently, such areas have 
come up to a pure stand of scrub pine which forms about 10 per cent 
of the forests of the northern half of the county. Formerly, the entire 
county was covered with a dense stand of hardwood timber with oaks, 
chestnut, and hickory predominating. The lands now occupied by the 
better forests are those which have never been cleared. These are narrow 
strips along the streams and Bay shores. 

In the central part of the coimty the surface is rather undulating, 
especially along the streams. The earlier settlers cleared the land at 
the foot of the hills; the later settlers enlarged the fields by taking the 
timber from the hillsides. The loose, sandy soil on these cleared slopes 



200 THE FORESTS OF ST. MARY's COUNTY 

was soon waslied down into the valley below, which rendered eroded 
areas unfit for further cultivation. (See Plate YlII). The more valu- 
able bottom land along tlie streams is being covered with sand and 
gravel, washed there from higher places. Natural tree reproduction on 
such eroded hillsides is very tardy. Scrub pine is the only tree which 
will reclaim such areas. Farmers are, however, very cautious about such 
clearing at the present time, and seldom clear any land which is liable 
to erode. 

Future of the Forest under Judicious Management. 

St. Mary's County dealers in lumber and railroad ties are very eager 
to see both public and private interest taken in the preservation of their 
forests, and particularly in the young growth. They realize that some 
systematic management should be instituted if reasonable returns are 
to be expected in the future from the timbered areas. Farmers and 
owners of timber tracts realize that the woodlands are constantly depre- 
ciating in value in spite of the greater demand for forest produce. The 
best timber having been cut, the farmer is eager to find a market for 
the less valuable species. Every farmer owns some forest land from 
which he draws his fuel supply, fence material, and saw logs for build- 
ing purposes. Frequently, ties, poles, and piles are cut during the 
winter to secure some income from the woodlot to pay taxes and other 
expenses, but usually very little care is taken as to where and how the 
trees to be cut are selected. 

Woodland owners can enhance the value of their timber considerably 
by making what is generally termed improvement cutting instead of 
chopping down trees indiscriminately. Improvement cuttings can be 
carried on in all woodlots in this county with excellent results by remov- 
ing overmature trees, and by thinning out undesirable species where they 
interfere with the growth or reproduction of more valuable kinds. Such 
a cutting gives the remaining trees enough room and light for their 
better development. There are numerous overmature and diseased 
chestnut, oaks, and red gum trees which are injuring the younger growth 
about them. These should be removed gradually as the material can 



MARYLAND GEOLOGICAL SURVEY. 



ST. MARY'S COUNTY, PLATE XVI. 




Fig. I. — VIEW showing reproduction of loi^lullv pine. 






•tl V 



'^m-. 



i3f^fe 










■^fk. 



Fig. 2. — VIEW showing method of transportation of loblolly logs to the mill. 



MARYLAND GEOLOGICAL SURVEY 201 

be utilized. In mixed hardwood forests, the selection system of cutting 
should be put in operation. The principal of the selection method 
is that the trees should be selected and cut here and there in the 
forest according to the owner's purpose. In this method trees may 
be removed from year to year as tliey reach a required diameter, and 
the wood from the top of those trees in addition to that which results 
from the cutting of inferior species and diseased trees will yield fuel 
supply for the owner. For the production of telegraph poles and 
railroad ties the trees may be cut as soon as they reach the desired 
diameter, and for wood for construction purposes, considerable thinning 
must be made so as to give the larger trees sufficient light and growing 
space. In this way the forest is opened rather uniformly and at the 
same time sufficiently to permit the reproduction of desirable species. 

In forests composed maiuly of oaks and chestnut, which sprout well 
from the stump, it may be advisable to cut most of the good-sized trees 
over a part of the tract for the purpose of raising a crop of sprouts. 
Stumps should be cut low and slanting, so as to prevent rotting and 
secure strong and numerous shoots. Trees from seeds are, however, more 
desirable than those from sprouts if large timber is the object. Sprouts 
are frequently defective at the butt. 

The pine forests are invariably even-aged and seldom need any furthei 
attention beyond that of protection from fire, which has thus far been 
no great source of damage in this county. The stand of pine necessarily 
needs to be rather dense, so that the lower part of the trunk will shed 
its branches early from want of sufficient light. In harvesting a growth 
of pine clear cutting is recommended with from 3 to 5 seed trees left 
distributed as uniformly as possible over every acre, if the area is again 
expected to grow up to pine. When broad-leaf trees are desired on 
such cleared areas, planting is advised. Acorns of red and white oaks 
may be planted four by four feet apart. Acorns for this purpose must 
be collected in early fall and put in boxes with alternate layers of sand. 
The boxes containing the acorns must be kept in a moist, cool place 
over winter. They may be buried in the earth about a foot below the 
14 



•<JU2 THE FOHESTS OF ST. MARY'S COUNTY 

surface of a well-drained hillside. In early spring, the acorns should 
be planted in hills. It is preferable to plant three acorns to a hill. 

The brush left after cutting may be burned where this is possible 
without injuring the trees left in the forest and at a season wlien there 
will be little langer of the fire spreading. Where this is not practicable, 
it should be scattered out over the forest floor so as not to be a hindrance 
to reproduction. 

The whole aim in forest management is to secure new trees of the most 
useful kind to take the place of those cut out as soon as possible after 
the removal of the old. For the best results it is essential that fire and 
grazing animals be kept out of woodlots. Fire running over the forest 
soil consumes the litter and kills the seedling and sprouts and reduces 
the vitality of old trees and frequently kills them outright. By the 
removal of the litter the forest soil is exposed and becomes too dry to 
encourage the germination of tree seeds. Grazing animals do consid- 
erable damage to woodlots and should be excluded. Cattle browse upon 
young growth and trample it down. Swine not only eat the nuts of 
the chestnut, oaks, and hickories, but they also dig up the forest soil 
and kill young seedlings and sprouts. 

]\Iuch damage to the young growth can be prevented if cuttings are 
made during the winter months, preferably when there is snow on the 
ground. Marking of trees may be done in the summertime when trees 
are in foliage, because at this time more accurate judgment can be 
exercised as to density of stand, condition, and health of trees. 

There is very little attention paid to the management of woodlots in 
St. Mary's County. It is a simple problem, however, and every farmer 
can regulate the cutting of the timber and improvement in such a manner 
that it will not prove a Imrden to him financially. Every farmer 
should fully realize that protection and selection of cutting are factors 
of prime importance in managing his woodlots to secure the highest 
financial returns. In case woodland owners desire a special and more 
detailed plan for the management of their woodlots, they should make 
application to the State Forester, Baltimore, Md. 

The demand for cordwooil for home consumption is not likely to in- 



MARYLAXD GEOLOGICAL SURVEY 203 

crease in this county luiless the proposed raih-oad slioidd he opened 
and the popnhition increased in the neiglihorhood of Point Lookout. It 
is believed, therefore, that it would not he profitable to manage a woodlot 
for the production of cordwood only, nnder present market conditions. 

Summary. 
The following is a summary of the principal facts determined by a 
brief study of the forests of 8t. Mary's County : 

1. Almost one-half of the area of the county is covered with forests. 

2. The most desirable timber has been cut. 

3. Formerly, the forests consisted of hardwood species. 

•Jr. At present, 20 per cent of the forests of the connty are scrub and 
loblolly pine, the pines tending to become the prevailing species. 

5. The most valuable timber now standing is white oak, loblolly and 
scrub pines. 

6. The hardwood forests are very nneven-aged and irregular in density 
of stand which renders lumljering difficult and unprofitable. 

7. The vdiite oak and chestnut which are the most valuable railway 
timbers are becoming scarce. 

8. Yellow poplar and scrub pine are largely cut for pulpwood. 

9. Eed gum which was formerly of little use and importance is now 
in demand for lumber and the manufacture of veneer. 

10. Fire and grazing which have retarded satisfactory reproduction 
have injured the mature tind^er of the county very little. 

11. Forest land could be nuide fully profitable by carrying out the 
following recommendations : (a) Eemoving dead, dying, and over- 
mature trees, (b) Eemoving mature or inferior trees which are 
suppressing or hindering desirable young growth from coming 
up in the forest, (c) In case of excessive cutting leave at least from 3 
to 5 seed trees to the acre, (d) Planting where desirable reproduction 
is not coming up reasonably soon after cutting, (e) Preventing fires and 
excluding grazing animals from areas where young growth is coming up. 



INDEX 



Abbe, CleTelaud. Jr., 50. 

Agricultural conditions, discussed, 139. 

Alexander, John H., 30, 41. 

Alexander map, 30. 

Alsop map. 27. 

Analyses of Leonardtown Loam, 129. 

of Meadow Land, 137. 

of Norfolk Loam, 127. 

of Norfolk Sand, 132. 

of Sassafras Loam, 133. 

of Sassafras Sandy Loam, 136. 

of Windsor Sand. 131. 
Areal distribution of Calvert formation, 
69. 

of Cboptank formation, 73. 

of Lafayette formation, 82. 

of St. Mary's formation, 76. 

of Sunderland formation, 85. 

of Talbot formation, 93. 

of Wicomico formation, 91. 
Areas of soils, 126. 
Artesian wells, 123. 
Atkinson, Gordon T., 5. 



B 

Babb, Cyrus C, 47. 

Bagg, R. M., Jr.. 51. 

Bailey, J. W.. 43. 

Barry, J. Neilson, 153, 176. 

Bassler, R. S., 52. 

Bauer, L. A., 18, 49, 51, 179. 

Baylor J. B.. 180. 

Berry. E. W.. 7. 

Bibbins, A., 7. 104. 

Bonsteel, Jay A., 17, 38, 50, 125. 

Boyer, C. S., 51. 

Building-stone, discussed, 118. 

Bushwood, artesian well at, 123. 



Calvert Cliffs, 68, 70, 72, 73, 74. 
Calvert formation, 68. 

areal distribution of, 69. 

character of materials of, 71. 

stratigraphic relations of, 71. 

strike, dip, and thickness of, 70. 

sub-divisions of, 71. 
Calvert water-horizon, 124. 
Case, E. C. 51. 
Cecil county, coastal plain in, 56. 



Chancellor Point, section at, 80. 
Chaptico, artesian well at, 123. 
Chaptico creek, 177. 

drainage area of, 177. 
Character of materials of Calvert forma- 
tion, 71. 
of Choptank formation, 74. 
of Lafayette formation, 83. 
of St. Mary's formation, 78. 
of Sunderland formation, 86. 
of Talbot formation, 95. 
of Wicomico formation, 92. 
Character and composition of forests, 

184. 
Charlotte Hall, temperature conditions 
at, 164. 
precipitation at, 173. 
snowfall at, 174, 175. 
meteorological summary for, 162. 
Cherryflelds, mean temperatures at, 153. 

precipitation at. 158. 
Chesapeake Group, 68. 

origin of materials of, 80. 
sedimentary record of, 98. 
Chestnut, 189. 
Choptank formation, 72. 

areal distribution of, 73. 
character of materials of. 74. 
stratigraphic relations of, 74. 
strike, dip, and thickness of, 73. 
sub-divisions of, 74. 
Clark, Wm. Bullock, 7, 9, 46, 47, 48, 49, 

50, 51, 52. 
Clays, discussed, 113. 
Cleaveland. Parker, 32, 39. 
Clifton i\Iills, section at, 93. 
Climate, discussed, 147. 
Climatic data, 148. 
Climatology of Charlotte Hall, 161. 
Coad, J. Edwin, 148, 176. 
Goad, J. Francis, 149, 161, 176. 
Coastal plain in Maryland, 56. 
Columbia Group, 84. 

origin of materials of, 97. 
sedimentary record of, 99. 
Commercial trees. 188. 
Conrad, T. A., 34, 40, 41, 42, 43, 44, 45. 
Contents, 11. 
Cordwood, 193. 
Cornfield harbor, 105. 

artesian wells at, 124. 
Cuckold creek, section at, 80. 
Cultural treatment of forests, 200. 



206 



INDEX 



Dall. W. ri., ?,1. 4(5. 47. 40, 52. 
Dana. .T. D.. 35, 45. 
Dartou, X. H., 36, 37, 47, 48. 
Day, D. T., 46. 
Desor, E., 44. 

Diatomacoous carlii. discussed, 120. 
Drainage, 59. 
Drum Cliff, 74, 75, 76. 
section at, 79, 93. 
Ducatel, J. T., 29, 41, 42. 
Dug wells, discussed, 122. 
r>uration of crop season, 172. 
J»uration of warm waves, 169. 
Duration of cold periods, 170. 



Eastman. C. R., 52. 
Economic resources, discussed, 113. 
Ellicott, James F., 148, 176. 
Eocene water-horizon, 123. 
Extremes of temperature at Charlotte 
Hall, 165. 



Hay, O. I'., 53. 
Hayden, H. H., 32. 39. 
Heilprin, Angelo, 35, 36, 45, 40. 
Herrman, Augustin, 28. 
Horrman map, 28. 
Herrmann, C. F. von, 17, 147. 
Higgins, James, 44, 45. 
Historical review, 25. 
Hoi lick, Arthur. 52, 53. 
Hoxton map, 29. 
Hyatt, Alpheus, 176. 
Hydrography, discussed, 177. 

I 

Illustrations. List of, 15. 
Infusorial earth. 120. 
Interiiretation of Geologic record, 9S. 
Introduction, 21. 



Johnson, A. N., 50. 

.Jones Wharf, section at, 70. 

Joy, Geo. W., 176. 



Fairhaven diatomaceous earth, 71. 
Farrer map, 27. 
Fence timber, 197. 
Finch, John, 32, 34, 40. 
Fisher, R. S., 44. 
Forests, discussed, 183. 
Forest fires, 197. 
Forest types, 187. 
Forest trees, 185. 

Fossils from southern Maryland. 33, 34. 
Fossils of the Choptank formation, 75, 
76, 79. 

of the Lafayette formation, 81. 

of the St. Mary's formation. 78, 
79, 80. 

of the Talbot formation, 103, 105. 
Future improvement of Forest lands, 
200. 



Geographic research in St. Mary's 

county, 20. 
Geologic research in St. Mary's county, 

31. 
Geology, discussed, 67. 
Glbbes, R. W., 43. 
Glenn, L. C, 52. 
Gravels, discussed, 118. 
(irifflth, Dennis, 20. 
Grover, N. C, 18, 177. 



H 



Harlan, R., 43. 
Harris, G. D., 48. 



Lafayette formation, 81. 

age of, 81. 

areal distribution of, 82. 

character of materials of. 83. 

origin of materials of, 83. 

sedimentary record of. 98. 

stratigraphic relations of, 83. 

structure and thickness of, 82. 
Lafayette stage, 61. 
Langleys Bluff, section at, 06. 
Lea, Isaac, 34, 40. 
Leonardtown, artesian wells at, 124. 

magnetic station at, 170. 

mean temperatures at, 154. 

precipitation at, 150. 

section near, 00. 
Leonardtown Loam, 127. 

mechanical analyses of. 120. 
liindenkohl. A., 47. 
Loblolly pine, 100. 
Local sections of Miocene age. 79. 

of Sunderland age, 90. 

of Talbot age, 05. 

of Wicomico age, 93. 
Lord Baltimore map, 27. 
Lucas, F. A., 53. 
Lyell, Sir Charles, 85, 43. 

M 

Maclure. Willinin, 25. 32, 30. 
Maddox. artesian well near, 123. 
Magnetic declination, discussed, 170. 
Markoe, Francis, Jr., 43. 
.Marls, discussed, 110. 



INDEX 



207 



Martin, G. C, 52. 
Blartenet map, 30. 
Maryland Geological Survey, 31, 37, 49, 

50, 51. 
Mathews, Kdward B., 7, 49. 
McGee, W J, 37, 47. 
Mcintosh run, 178. 

drainage area of, 178. 
McWilliams, Alexander, 148, 176. 
Meadow Land, 136. 

mechanical analyses of, 137. 
Mechanicsville, magnetic station at, 180. 
Meelj, F. B., 45. 
Mell, C. D., 18, 183. 
Meridian line, 180. 

instructions for using, 180. 
Merrill, Geo. P., 49. 
Meteorological stations in county, 176. 
Meyer, Otto, 36. 
Miller, B. L., 7, 17, 113. 
Millstone, artesian well at, 124. 
Miocene, 68. 

local sections of, 79. 

origin of materials of, 80. 

water-horizon in, 123. 
Morton. S. G., 34, 40. 

N 

Natural deposits, 113. 
Newton, R. BuUen, 51. 
Nomini Cliffs, 72. 
Norfolk Loam, 126. 

mechanical analyses of, 127. 
Norfolk Sand, 131. 

mechanical analyses of, 132. 
Nuttall, Thomas, 32. 



Oakley, artesian wells at, 123. 
Origin of Lafayette materials. 83. 

of Miocene materials. 80. 

of Pleistocene materials, 97. 



Patterson, H. J., 119. 

Pearson, artesian well at, 124. 

Physiography, discussed, 55. 

Piles, 196. 

Piney Point, artesian well at. 124. 

Pleistocene, 84. 

origin of materials of, 97. 
Pliocene, 81. 
Plum Point, 71. 
Porto Bello, mean temperatures at. 1.j4. 

precipitation at, 159. 
Potomac river, section on, 96. 
Precipitation, discussed, 158. 
Precipitation at Charlotte Hall, 173. 
Preface, 17. 
Pulpwood, 195. 



Quaternary clays, discussed, 115. 



Railway ties, 194. 

Rau, Chas., 46. 

Recent deposits, 96. 

Recent stage, 66. 

Red gum, 188. 

Red juniper, 191. 

Remseu, Ira, 5. 

Ridge, mean temperatures at, 153. 

Ries, Heinrich, 51. 

Robinson, Samuel, 40. 

Rogers, H. D., 43. 

Rogers, W. B., 34. 41, 43. 



St. Clement river, 178. 

drainage area of, 178. 

section on, 90. 
St. George's island, artesian wells on, 

124. 
St. Inigoes, artesian wells near, 124. 

mean temperatures at, 155. 

precipitation at, 160. 
St. Mary's, mean temperatures at, 154. 

precipitation at, 159. 
St. Mary's County, agricultural condi- 
tions in, 139. 

artesian wells in, 123. 

building-stone of, 118. 

clays of, 113. 

climate of, 147. 

diatomaceous earth of, 120. 

drainage of, 59. 

dug wells in, 122. 

economic resources of, 113. 

forests of, 183. ?^ 

geology of, 67. 

gravels of, 118. 

hydrography of, 177. 

magnetic declination in, 179. 

marls of, 119. 

meteorological stations in, 176. 

miocene in, 68. 

pliysiography of, 55. 

pleistocene in, 84. 

pliocene in, 81. 

t)recipitation in, 158. 

recent deposits of, C6. 

sands of, 117. 

soils of, 125. 

soil types in, 126. 

springs in, 121. 

structure of coastal plain in, 61. 

table of precipitation in, 157. 

table of temperatures in, 152. 

temperature conditions in, 151. 



208 



INDEX 



thermal anomalies In, 155. 

topographic description of, 56. 

topographic history of, 61. 

transportation facilities in, 23, 144, 
192. 

water resources of, 121. 

wood consumption in, 102. 
St. Mary's formation, 70. 

a real distrilmtion of, 76. 

character of materials of, 78. 

stratigraphic relations of, 78. 

strike, dip, and thickness of, 77. 

sub-divisions of, 78. 
Sands, discussed, 117. 
Sassafras Loam, 133. 

mechanical analyses of, 133. 
Sassafras Sandy Loam, 134. 

mechanical analyses of. 13G. 
Sawmills and their products, 103. 
Say, Thomas, 40. 
Scharf, J. Thomas, 47. 
Scott. Joseph. 30. 
Scrub pine, 100. 

Sedimentary record of Chesapeake 
Group, OS. 

of Columbia Group, 90. 

of Lafayette formation, 08. 
Sellards, E. H., 53. 
Shaler, N. S., 45. 
Shattuck, George B., 7, 17, 25, 50, 52, 53, 

67. 
Silvester, R. W., 5, 153, 176. 
Sioussat. St. George L., 50. 
Smith, John, 25, 28, 38. 
Smith map, 26. 

Snowfall at Charlotte Hall, 174. 
Soils, discussed, 125. 
Soil types, 126. 
Sotterly, artesian well at, 124. 

section near, 06. 
Springs, 121. 
Staggs, T. G., 148, 176. 
Staves, 197. 

Stephenson, James, 148, 176. 
Stratigraphic relations of Calvert forma- 
tion, 71. 

of Choptank formation, 74. 

of Lafayette formation, 83. 

of St. Mary's formation, 78. 

of Sunderland formation, 87. 

of Talbot formation, 05. 

of Wicomico formation, 02. 
Strike, dip, and thickness of Calvert 
formation, 70. 

of Choptank formation, 73. 
. of St. Mary's formation, 77. 
Structure of Coastal plain, 61. 
Structure and thickness of Lafayette 
formation, 82. 
of Sniulcrland formation, 86. 



of Talbot formation, 94. 

of Wicomico formation, 91. 
Sub-divisions of Calvert formation, 71. 

of Choptank formation, 74. 

of St. Mary's formation, 78. 
Sunderland formation, 85. 

arcal distribution of, 85. 

character of materials of, 86. 

local sections in, 00. 

stratigraphic relations of, 87. 

structure and thickness of, 86. 
Sunderland stage, 62. 
Susquehanna gravel, 129. 
Swamp land, 138. 
Swartz, C. K., 7. 



Talbot formation, 03. 

areal distribution of, 03. 

character of materials of, 05. 

local sections in, 05. 

stratigraphic relations of, 95. 

structure and thickness of, 04. 
Talbot stage, 64. 
Telegraph poles, 106. 
Temperature conditions at Charlotte 

Hall, 164. 
Temperature conditions in St. Mary's 

county, 151. 
Tertiary clays, discussed, 114. 
Thermal anomalies, 155. 
Topographic history, 61. 
Transmittal, Letter of, 9. 
Transportation facilities, 23, 144, 192. 
Tripoli. 120. 
True, Frederick W., 53. 
Tyson, P. T., 44, 45. 

U 

Uhler, P. K., 46. 

U. S. Bureau of Soils, 17. 

U. S. Coast and Geodetic Survey, 30. 

U. S. Department of Agriculture, IS. 

U. S. Forest Service, 18. 

U. S. Geological Survey, 18. 

U. S. Weather Bureau, 18. 

Ulrich, E. O., 52, 53. 

V 

Van Renssellaer, J., 33, 40. 
Vanuxem, L., 34, 40. 
Variation of the compass, 182. 
Vaughan, T. W., 52. 
Veneers, 190. 

W 

Wagner, William, 42. 
Wailes BlulT, section at, 96. 



INDEX 



209 



Warfleld, Edwin, 5, 9. 
Water-horizoug in Eocene, 123. 

in Miocene, 123. 
Water i-esources, discussed, 121. 
White oali, 189. 
Whitney, Milton, 48. 
Wicomico formation, 91. 

areal distribution of, 91. 

character of materials of, 92. 

local sections in, 93. 

stratigraphic relations of, 92. 

structure and thickness of, 91. 
Wicomico stage, 63. 
Williams, A., Jr., 46. 



Williams, G. H., 48. 
Winds and weather, 176. 
Windsor Sand. 130. 

mechanical analyses of, 131. 
Wood consumption. 192. 
Woolman, Lewis, 47. 



Yellow poplar, 188. 



Zones of the Choptank formation, 74. 
Zones of the St. Mary's formation, 78. 



,n:'r.°^^o^^^ 



^014 440 717 



n 



